00ac's manga / #Student x Student(81)

Confident, Bottom Mc- he's essentially a male succubus (or 'incubus') with an addiction to jizz to sate bloodlust. One day, he does go after a fellow classmate (the ML) when he goes too long without feeding, and it turns out that the ML is essentially his 'sanguine cantanto' or basically he's a match for him. Mizuki is a modern-day vampire who lives with some debauched eating habits, controlling his bloodlust with a bodily fluid that's a little whiter than blood. He always finds his meals outside his personal social circle, but when he loses control of his bloodlust, he accidentally assaults Sakura, a younger student from his college...! Mizuki's reason and instinct waver as he suddenly discovers a "delicious delicacy.

MC- (top) always has his girlfriends stolen by his best friend, ML (bottoms). They both like each other.

Not a reread

Starts off rocky and toxic but gets better??? The bottom does become possessive towards the end too and is the one to cement the relationship (chapter 6)