Clap-on

Okay. Here's what you do:

1. Order the clapper (of "clap-on, clap-off" fame);

2. Install the clapper prior to your Dom's/top's arrival;

3. Make a snarky remark;

4. Let the fun ensue.

Probably not the most original gag, but it beats drawing a bulls-eye on your butt.

And I also think I just tipped my hand. I'll let you know how it works out for me.