When being pegged I am always worried about soiling the toy. I can never quite relax because it feels like I'm going to... well you know... drop a Hershey's Kiss. What do you do to make sure the cost is clear? I assume a bathroom break but what else?

Let me assure you that half of that is in your mind.  The other half is a result of you tensing up expecting an accident.  Couples things I recommend:

1. Practice with a dildo on your own or wear a plug to get use to the sensation of being filled.  Rectums are meant to expel things, not the opposite so there will be a bit of mind over matter so to speak.

2. Read these cleaning tips.

3. Relax and have a good time.  If a little accident happens, it’s not the end of the world.  Have some wipes handy and talk to your partner about your fear.  She will put it to rest that it’s no big deal.