Ok, this appears to be a gag-manhwa, so very much not my scene. Instantly dropped. An orphan is adopted by a super naive sadist master who basically torments him physically for training and tries to motivate his student with offers to breastfeed him despite the fact that, that isn't within the capabilities of a man. At least in this story. So basically now that student is pretty much an adult, the master is also sexually harassing him too, though I guess he doesn't mean it that way. Anyway, it's a comedy story where you're definitely not supposed to take anything seriously although, I have no idea why the main couple have to be an old man who raised the his lover from a baby. That's just ick. Why??? Author why did you make it like that???? Why couldn't he have met him in adulthood??? Why did he need to be a baby first???? Author???? Hello?!
What kind of rubbish are you cultivating?