Make them jerk you off.

"Here's my plan," you announce, "I want each of you to jack me off for three minutes each. The first girl to make me cum is my **** for the week. For that week, the rest of you are off the hook, but then the game starts over with the original **** out of the loop. When you've all gone, we start over with a different game."

The girls nod.

'Now Rachel," you say, "this is your party, so it's your job to start."

Reluctantly, she walks over, drops to her knees, and takes your caok in one hand, playing with your balls with the other.