Looks okay to me.

She stands their looking herself up and down. You yourself get an eyeful in the process and you pants start to tighten. You have already come this far so you break the silent stare. "Looks good to me." you say. She reaches for a towel and faces you. "What the fuck are you doing here?" she says. You explain that you noticed her in the shower and ask if she is certain she didn't miss any spots which you would be happy to help her with.
She only stares, still embarassed.
"If you've got a problem I can always go give this to your mom." You motion to the pressing urge in your pants. She gasps, just now noticing the monster beneath your swim trunks trying to break free.
"my mom?" she says. "that bitch. Get your ass in here before she sees you.