At Ch8, subordinate seme (Aesang) resigned and then wished a curse upon his bad boss (Hanseol). At Ch 9, their souls woke up at each other’s bodies, which means although we see Hanseol waking up at Aesang’s house and Aesang calling him from the CEO’s office, we’re actually just looking at their souls. The bodies they inhabit are the other person’s which is shown only when they look in the mirror and as how other characters see them. They themselves don’t perceive the switch when looking at the other person, which means to say that Hanseol can only see that he is inside Aesang’s body when looking at the mirror and he still sees Aesang as Aesang even though in real life, he should be looking at his own face and body with another soul inhabiting it. Notice how at Ch 11, when Hanseol was doing the crazy ritual dance, Aesang did not find it funny or strange until he noticed the reflection of the dancer on the glass windows and saw it was actually his own face and body being used by Hanseol to dance. In Ch 12, they were talking about how Hanseol slapped Aesang and how it shouldn’t hurt their feelings as they were essentially just slapping their own bodies but Aesang couldn’t slap Hanseol because even though he knew it was actually his own body that he was slapping and not actually Hanseol’s face, he said: “Sure, you’re in my body… but what I see in front of me is you, Hanseol.” Then in Ch 13, when they started kissing, we see these sparkles and this pink aura-like effect, which I first assumed was just to give the panel a romantic feeling, but was actually visible to them, just that Aesang was too far gone and Hanseol was too intoxicated to actually pay attention to it, maybe he even thought he was just dizzy and seeing things. This effect was actually the indicator that they had already switched their bodies back. They don’t notice because even though they were in each other’s bodies, they still retained their perception of the other and their own body’s senses. Hanseol said: “So I’ve been thinking about this. Even though our souls have switched places, the physical sensations I feel are exactly the same, isn’t that strange?” He described it as “It’s as if we’ve entered an upside down world where both our minds and bodies remain the way they used to be.” He further said: “Are you sure you’re okay with this? Even though what we see is each other (Hanseol see Aesang and vice versa)… in reality, it would be me doing you.” They still haven’t realized that they’ve already switched back since the kiss so everything afterwards was actually Aesang topping Hanseol both in reality and in their perspective and there was never anything like Hanseol’s body topping Aesang’s body. Their perspective of each other even when in the other’s body really doesn’t change from their original and they’re also high on alcohol so it would have been pretty hard to notice the switch back. In Ch 14, there were hints like Hanseol thinking that his body’s erection (that Aesang should have had) should really not have been as big as what he’s feeling at the moment coming from Aesang and Aesang saying that no matter what, he really feels like he’s touching the real Hanseol even though it should have logically been his own body that he was touching at the moment. Ch 15 is when Hanseol first realized that something was not quite right since his own body should not have had the stamina that Aesang currently had so he starts to doubt if their souls really had been switched in the first place, then a thought comes and he realizes that maybe at some point in the very immediate past, they might have already switched back into their original bodies and just hadn’t noticed yet so he starts looking for a mirror but it wasn’t until quite some good time later that they were finally able to check and confirm that they had indeed switched back to their own bodies through the bathroom mirror when their reflections were the correct faces and bodies. Hanseol then suspects the strange light he thought was just his imagination, while Aesang was just confused and unaware, having not noticed the phenomenon Hanseol did. They were also unsure what the trigger was (they were reasonably suspecting the sex) but they were pretty convinced the light was the indicator of the switch. And that’s the end of that for the body swap.
At Ch8, subordinate seme (Aesang) resigned and then wished a curse upon his bad boss (Hanseol). At Ch 9, their souls woke up at each other’s bodies, which means although we see Hanseol waking up at Aesang’s house and Aesang calling him from the CEO’s office, we’re actually just looking at their souls. The bodies they inhabit are the other person’s which is shown only when they look in the mirror and as how other characters see them. They themselves don’t perceive the switch when looking at the other person, which means to say that Hanseol can only see that he is inside Aesang’s body when looking at the mirror and he still sees Aesang as Aesang even though in real life, he should be looking at his own face and body with another soul inhabiting it. Notice how at Ch 11, when Hanseol was doing the crazy ritual dance, Aesang did not find it funny or strange until he noticed the reflection of the dancer on the glass windows and saw it was actually his own face and body being used by Hanseol to dance. In Ch 12, they were talking about how Hanseol slapped Aesang and how it shouldn’t hurt their feelings as they were essentially just slapping their own bodies but Aesang couldn’t slap Hanseol because even though he knew it was actually his own body that he was slapping and not actually Hanseol’s face, he said: “Sure, you’re in my body… but what I see in front of me is you, Hanseol.” Then in Ch 13, when they started kissing, we see these sparkles and this pink aura-like effect, which I first assumed was just to give the panel a romantic feeling, but was actually visible to them, just that Aesang was too far gone and Hanseol was too intoxicated to actually pay attention to it, maybe he even thought he was just dizzy and seeing things. This effect was actually the indicator that they had already switched their bodies back. They don’t notice because even though they were in each other’s bodies, they still retained their perception of the other and their own body’s senses. Hanseol said: “So I’ve been thinking about this. Even though our souls have switched places, the physical sensations I feel are exactly the same, isn’t that strange?” He described it as “It’s as if we’ve entered an upside down world where both our minds and bodies remain the way they used to be.” He further said: “Are you sure you’re okay with this? Even though what we see is each other (Hanseol see Aesang and vice versa)… in reality, it would be me doing you.” They still haven’t realized that they’ve already switched back since the kiss so everything afterwards was actually Aesang topping Hanseol both in reality and in their perspective and there was never anything like Hanseol’s body topping Aesang’s body. Their perspective of each other even when in the other’s body really doesn’t change from their original and they’re also high on alcohol so it would have been pretty hard to notice the switch back. In Ch 14, there were hints like Hanseol thinking that his body’s erection (that Aesang should have had) should really not have been as big as what he’s feeling at the moment coming from Aesang and Aesang saying that no matter what, he really feels like he’s touching the real Hanseol even though it should have logically been his own body that he was touching at the moment. Ch 15 is when Hanseol first realized that something was not quite right since his own body should not have had the stamina that Aesang currently had so he starts to doubt if their souls really had been switched in the first place, then a thought comes and he realizes that maybe at some point in the very immediate past, they might have already switched back into their original bodies and just hadn’t noticed yet so he starts looking for a mirror but it wasn’t until quite some good time later that they were finally able to check and confirm that they had indeed switched back to their own bodies through the bathroom mirror when their reflections were the correct faces and bodies. Hanseol then suspects the strange light he thought was just his imagination, while Aesang was just confused and unaware, having not noticed the phenomenon Hanseol did. They were also unsure what the trigger was (they were reasonably suspecting the sex) but they were pretty convinced the light was the indicator of the switch. And that’s the end of that for the body swap.