The phrase "bounce when she walk" comes from the song "Bounce When She Walk" by OhBoyPrince featuring MykFresh and GwallaGangSpec. It refers to how a woman's body, particularly her buttocks, moves in a bouncing and clapping motion as she walks or dances. The song describes this movement as attention- catching and appealing, emphasizing shaking and clapping of the buttocks everywhere she goes. It is a celebration of the physical movement and confidence in how she carries herself, often associated with twerking and dance culture.
In summary, "bounce when she walk" describes the noticeable, rhythmic movement of a woman's posterior when she walks, creating a "bounce" and "clap" sound or effect, which is highlighted in the song lyrics and popular dance trends connected to it.