Wit's manga / #judo(2)

After getting dumped a guy gets a letter in his locker that tells him to meet behind the dojo. But instead of a cute girl waiting to ask him out its his kouhai from judo. But being an open minded dude (who really only thinks about sex all the time) he says why not and they start dating

Guy goes to college to find his old judo partner and rival only to find out that he has quit judo for good. To change his mind he challenges him to a match, but if he loses he has to give him a blow job...