Asking for sex in LTR in needy. Demanding it is dominant, but can be rapey. What are some other clever ways of "asking" for sex.

Having high SMV and expecting to get a blowjob whenever you want is a bit too good to be true all of the time. Sometimes you're just not at the top of the game. What are some clever ways of bringing the topic or initiating sex without sounding needy or rapey? Any good practical techniques are welcome.