Looking for a BL

it's a harem BL manhwa where mc is a sex education teacher. There's a dragon egg and they hired teachers for the egg, but the egg never hatched for years and all teachers decided to quit while mc remained loyal to his job to the point he started talking to himself (teaching the egg) Abt sex Ed. he makes sex toys to teach the egg and then one day while he tests out the new toy he made in front of the egg, the egg suddenly hatched and it's a huge ass muscular dragon that looks like a human instead. Then slowly, other characters came and in the end, he got pregnant by all of them (i forgot how many they were)