Si papi is used during sex, oral or anal (doesn't matter). It means yes daddy.
Girl: Si papi!
Guy: Yea, you like that
meaning "yes daddy" in Spanish. Mainly used in a sexual form
Oh si papi! Fuck me harder until I come! Oh baby yes!
Spanish for "yes daddy". You usually say it when you are asked a yes or no question. Or if the teacher tells you too do something. No matter if the teacher is a guy or a girl.
Spanish teacher says "Timmy, did you bring an std to school again dear?"
YOU: SI PAPI !!!!
Spanish teacher says: "Get your hand off of my ass!"
YOU: "SI PAPI !!" and proceeds to grab her pussy instead.
Isabella: Si papi! Si papi! Si papi! Yo quiero mas papi!
Juan: You like my horse cock?