He consented to seme? When? Did we not read the same chapters? If he did, please tell me what I've missed , because at page 18 of chapter 20, he clearly didn't know seme was going to continue to pound his ass in his unconsciouness.
http://www.mangago.zone/read-manga/down_and_dirty/uu/iur_chapter-20/pg-18/
I think what your talking about is page 5. Even then, it is not consensual because Seme says : "is it okay to continue?" But it is not about if he can continue after uke passed out, it's about if he can continue thrusting for THE MOMENT. RIGHT NOW. NOT AFTER he passed out. CNC or limp sex/unconscious sex was NEVER evoked. Plus, uke question about seme continuing after he passed out after the event is a CLEAR STATEMENT THAT UKE DIDN'T KNOW SEME WOULD HAVE INTERCOURSE WITH HIS BODY IN HIS SLEEP. Thus making it non-consensual, thus rape. Uke is too much of a doormat, too much in his feelings, wrapped around seme's finger and scared of losing unworthy piece of shiet seme to realize that. There was no consent. PERIOD.
I REST MY CASE.

Once a person passes out, they can no longer consent to a sex act therefore it is rape or at the very least sexual misconduct. Just because the uke is crazy enough to be fine with it doesn’t make it less fucked up.
That said, I’ll keep reading just to see how this dysfunction ends.