I learned the rhythm part of that game from the “Zoom” television show (shows you how old I am.) You maintain a rhythm by hitting both your thighs at the same time with both your hands, then clapping once, then snapping with first your left hand then your right. So there’s 4 parts to the rhythm. While maintaining the rhythm, you say:

hands up and 85
we’re gonna get
the names of
(pick a subject, like “girls)
no repeats
no hesitation
no obligation
so let’s go
to the show
ready or not
here we go
starting with…

then each person has to say a girl’s name starting with letters of the alphabet. (like Allison, then Betty, then Carla, etc.) Until someone misses the beat or can’t come up with a name. The answers fall on the thigh clap and the next person has to say a name on the next thigh clap.