One of my favorite pastimes:
Lube up your favorite Aneros and send it home. Cue up one of the Cock Hero Gay vids. Meditative state is one of my top choices for bottoming. Get comfy horizontal.
Circle your nips in the warmup and breaks. When the beat bar gets going, flip them with each beat. Encourage your sphincters to clench along in rhythm. They will. Be sure to open up your ass so your toy moves freely.
When everything is humming along, take a break from your nips, and enjoy your ass continuing to quiver and hug the toy along with the beat, without any encouragement except your ecstatic state of mind.
That sounds like fun. I might have to try that soon.