An act traditionally geared to titillating by presenting the appearance of revealing a dancer's (usually of the feminine variety) naughty bits.
A famous version frequently had the dancer behind large fans or feathers the entire time, with only bare legs or arms peaking out as cloths were periodically flung off into view. Hence the "tease" in the name.
Today there is frequently no tease involved. Some music is played, generally too loud and all the clothes (if a bikini counts) are flung off and the dancer bounces around collecting cash.