Wear the special disposable underwear from the feet up to the pelvis, as you would wear regular underwear, with the side with the adhesive at the back.
Secure it high up towards the waist to achieve a good fit in the crotch. Smooth out the gathers at the waist so that it fits ideally on the body.
When you want to change the underwear, tear the two side seams from the waist downwards. Open the underwear and remove it carefully. As you remove it from your body, wrap it carefully and seal it with the adhesive.