
for everyone who still doesn't get it:
the top (dominant sadist) thought he'd found a submissive masochist in the bottom. they made a contract about their relationship. the top was very clear about wanting to keep the relationship purely sexual. iirc he even set it down as a rule. the bottom fell in love (or at least developed some kind of feelings for the top) and wanted the relationship to become romantic, but he was afraid that if he told the top, the top would end their relationship altogether. so instead he kept on pretending that he's a masochist even though he did not like getting hurt during sex, and by that he was essentially misusing the top's trust and breaking rules of their contract.
in that last chapter, the other guy purposefully called the bottom out on his lie so that the top would overhear it.

the fact that we never got to see that mushroom in action... tragic

http://www.mangago.zone/read-manga/form_of_sympathy/ They just have 3 episodes translated ╥﹏╥
But the raws have 23 chapters https://tkor.vin/%EB%8F%99%EC%A0%95%EC%9D%98%20%ED%98%95%ED%83%9C and you can see them in action at the end of chap 16 (〜 ̄△ ̄)〜

my stomach literally dropped when the alpha threw him on the bed. there are so many nice ways this whole "hides that he's an omega"/"thinks he failed as an omega" thing could have played out and instead we get... this garbage
like imagine the alpha didn't outright rape him but came to stay with him and slowly pieced together that he's an omega... he'd have worked out why he hides his omega part... and then he'd have helped him realize that he's a perfect omega while gently and consensually bedding him... SIGH
"if you really don't like it, how about you try saying no properly?"
if you really wanna fuck him, how about you try asking him about it first?
"how about you try saying no properly" could have given the whole thing a sense of dubious consent at least IF the guy hadn't clearly said "get lost", "let go" and "quit it" before that. so the top is still an asshole and it is still rape, good bye