Use one on your penis (male).

You slip one portal over your quickly rising member, stretching the edge over your nutsack and then making it smaller again once you're past. Looking at your crotch, all you see is the inactive side of the portal. You look over at the table where you have the other end, which currently has your cock and balls sticking upwards out of the active side. You grab your dick, noticing how weird it feels to be holding it at arm's length but still feel the sensations of your hand on your shaft.