“Boule” in this case is a familiar way of saying ass.
The correct way to write that is :

Elle t’a donné son boule

Meaning more or less :

Elle a couché avec toi

Alternatively, boule in mistake-riddled elle ta donné son boule might refer to furniture made by 17th-century cabinet-maker André-Charles Boulle, commonly known as boulle, singular un boulle.

https://upload.wikimedia.org/wikipedia/commons/e/ee/Musée_du_Louvre_-_Département_des_Objets_d%27art_-_Salle_34_-2.JPG