Roll +cool to stalk them (+3 cool, -1 for four girls, +2 total)

On a 10+ you find them alone and ready, no problem.

You've been watching Cindy for months, waiting for your chance, and you've done your homework. You go quietly around to the back of the house, let yourself in, and enter the pasword for the alarm system. You can hear the four girls giggling upstairs. You move quietly through the house to the hall outside Cindy's bedroom. Cindy's bedroom door is open just enough that you can see the girls in the mirror. You move into the bathroom across the hall from Cindy's room, and sit on the edge of the tub, positioning yourself so that you can see Cindy's mirror reflected in the bathroom mirror.

True to their word, the four little schoolgirls are showing off the lacy, frily underwear they just bought at the mall.