If Blac Chyna is upset about her sex tape leaking to the world ... she sure as hell wasn't showing it during what looks like a sexy sleepover party with Amber Rose -- and her baby girl, Dream.
BC was strutting her stuff in an animal-print onesie Monday evening ... 12 hours or so after the video of her performing oral sex hit the Internet. Her BFF, Amber, gave her props, shouting ... "Dreamy's mom got it going on." Yes, Dream had a front row seat for the action.
TMZ broke the story ...Chyna's attorneys say the sex tape release is a "criminal act" which they've reported to cops. Ditto for the guy in the video -- her ex, Mechie, tells us he also wants the leaker prosecuted.
Guess she's leaving it to the lawyers to sort out ... 'cause Dream's mommy doesn't look like she's losing sleep.
BTW ... Twitter's already shut down the account that first posted the sex tape, saying the video appears "to have been taken or distributed without the subject's consent."