'Big Brother' Sexual Hijinks, Butt Poking Rampant, 'You Punched My Vagina!'

The "Big Brother" house is a cauldron of sexual shenanigans ... or so it seems judging from the 24-hour live feeds.

It's shocking ... a male cast member grabbing Jessica Graf's vagina, women butt poking men, men butt poking women, men butt poking men, and it's all on video.

TMZ broke the story ... Jessica appeared to start it, and it seemed it was to the dismay of other housemates. But now we see, it's become a thing in the house.

These latest clips show Matthew Clines, Paul Abrahamian, Ramses Soto and Elena Davies all partaking in a sneak butt poke or two. Paul gets 2 off, both on male cast members ... one of whom Elena also pokes. Jessica Graf even accuses Matt of punching her vagina ... and her roommates laugh.

It's interesting ... Matt called Jessica a sexual predator when she poked his ass, and Paul later complained to Kevin about Jessica's ongoing poke joke in the house.

We got Les Moonves out at Craig's last night and he said he hadn't seen the footage of Jessica, but he would watch it today.