Anal Bead

   To most people anal beads are just sex toys they stick in their butts,
   however anal beads with with remotely controlled vibration can also serve
   as a well hideen one-way communication device. Use of an anal bead for
   cheating in [1]chess has been the topic of a great cheat scandal in 2022
   (Niemann vs Carlsen).

Links:
1. chess.md