The not so obvious thing to do with a bathing cap is take a cap with a lot of flowers and frills and turn it inside out. Hold the cap in place over your penis with a rubber band daisy chain around your waist and attached to the chinstrap snap points.
As the penis erects and when it gets a little stimulation, it jerks. The jerking rubs the penis against the rubber pedals and frills in the cap design. This stimulates it again, and it jerks again. The result is a perpetual, almost subliminal tickling stimulation, resulting in perpetual arousal and being brought closer and closer to the edge of orgasm, but never really getting there.
If you are up and about while wearing the cap and doing some sort of exercise or dancing that causes your penis to jiggle inside the cap, then you might be able to achieve orgasm. I have never been able to do it, but the cap has kept my penis hard for hours. It makes a wonderful 'tease toy.'