Since they already said Cynthia's not involved, that eliminates her. Kandi doesn't drink so I'm sure the only thing she probably did was grind on Cynth like she did at her burlesque show. Kenya's confirmed not to be involved, but she does get on the culprit for it and cackles at her or them. Drew's boring ass probably went to be early to read Bible verses and spiritual quotes.
That leaves Porsha, LaToya, Falynn, Marlo, and I don't see Pennywise engaging in that since she's so in love with being a forever fiancé to Paul's ass.
Porsha's gotta be the one getting that pussy pummeled. Dennis dumped her for Velvet, Twirl, and King so she gotta get off somehow and Falynn supplied the coke to get them on a high.