In the My Collection tab, click on the card you wish to use. When the card detail opens, click on the clip selector shown in a circle on my screen shot. ***** the desired clip to the Next section of the Now Playing tab (click to open). Make sure the Repeat checkbox in the lower right is on. The clip will repeat until you quit iStripper or change what's in the Next section. If you put more than one clip in the Next section they will play in a cycle.

If the clip selector does not appear, go to settings, turn on advanced settings and in Display group check the display clips list checkbox.

A more complicated but reusable approach is to create a playlist and then play it. For example, I have a play list of nothing but window washing clips.