Urethral "play" is not a 'normal' or safe thing to do.. BUT, if the one inserting knows what they are doing, it can be rather interesting! My first play partner that was into my chastity was a nursing student. She practiced her catheter insertion and maintenance techniques on me and this led to other medical play, as well as experimenting/exploring chastity with a urethral tube installed. Anything stuck in there should be intended to go in there and kept extremely clean! Be safe and have fun.