Because I need to see your structure before, during, and after the session most clients, both men and women, go through the sessions in either a two piece bathing suit for women, or boxer briefs for men.  Fitted gym shorts, biking shorts, and sports bras are also fine (the less area of the back the sports bra takes up the better). Once you are on the table, you can have a sheet or blanket to cover up with if you wish.