Reddit mentions of Panic Snap

My wife loves being restrained! And I like restraining her. You and your friend should communicate about what sort of fun she has in mind.

It sounds like your friend is probably thinking about giving you sexual pleasure (or asking you to serve her sexually) while you're restrained, so be really clear on what sex acts you do and don't want to participate in once you're tied up.

• Can she use a vibrator on you while you're tied up?
  
• Can she use her fingers or mouth to bring you to orgasm?
  
• Would you prefer some/all of the above, but no orgasm?
  
• If she uses dildos or other insertable toys, do you want her to put condoms on them to be sure there's no microbial transfer?
  
• Would you like her to straddle your face and order you to lick her?
  
• Would she like to stand or kneel over you and get herself off, while you watch, unable to participate?
  
• How about thoroughly-washed asses? I'm sort of out on a limb here but do people eat ass "just for fun, with friends"?
  
• Once you've been tied up, does she want to take a turn being tied up?
  
• Have you considered buying a few panic snaps to add to the tie-up, so that you can quickly release yourself if things go south?
  
  All of those are options that you might try, but unless you talk it through, you won't know for sure. Ask your friend whether she knows if she's gay, bi, etc. -- ask if she has romantic feelings for you, or if this is really more about having a safe friend to try erotic things with? You might not want to do this "just for fun" if it's going to be a powerful emotional turn-on for her.