Use 3M Transpore surgical tape. It's waterproof, transparent and stays on clean, dry, shaved skin until you pull it of. I even shower with it. I use 3 horizontal strips of 1 inch wide tape. Top piece is 4 inches long and the 2 lower ones are each 2 inches long. Leave a small gap at the bottom and you don't need to untape to potty.
Downside is that it does leave a little adhesive residue but you can also buy the remover. Tape is sould at any pharmacy or pharm department in Walmart, etc.