Yes, topless spin the bottle was a thing

Matt busied himself taking drink orders while Giang played bartender mixing, Matt thought, stronger drinks than any bartender ever would. After an hour, Cai pulled an awning out from the house casting shade and a bit of privacy onto the deck.

"In traditional Asian culture, suntan is seen as a bad thing." Pam grasped him by the arm and whispered into his ear, probably sending a message of ownership to the other girls and conveying the impression that she was murmuring little love notes. Instead he was getting a lecture on Asian culture. "Us second and third generations have gotten more Americanized, which is why you saw us in bikinis in the sun but we still don't want to get too much. It makes our parents think we're peasants."

"Very interesting," Matt lied.

She punched him in the arm. "If someone once told you sarcasm is sexy, they were leading you astray. Now come on, we're going to play a game."

Spin the Bottle seemed a bit juvenile to Matt... he'd last played it in junior high school. On the other hand, he hadn't played it with a bunch of college girls in bikinis. And the rule about girls taking off their bikini tops had definitely not been part of his junior high school experience.

There was much giggling and laughter when Betty, who went first, spun Pam. The two girls went at each other, giving tongue and squeezing boobs while Matt decided to save up his tutoring money and buy an inconspicuous camera he could mount somewhere.

Cai, who went first, spun her brother. "I think that's a Mulligan," Giang said.

"Noooo," the girls chanted. Finally Cai walked over to her brother's chair and gave him a chaste kiss on the cheek... at least that's how she started because Pam grabbed Giang's hands and placed them on his sister's tits while Betty pressed their heads together until they gave up and french kissed each other.

Both were bright red and breathing hard by the time Betty let them go. Matt noticed Pam had dropped Giang's hands at least a minute before they stopped kissing but he hadn't let go of his sister's breasts.