Toilet breaks... wetting yourselves is neither hygenic or proper to do. It can lead to a severe rash on the genital area, and do you really want your friend/BF/GF to have that.... they will probably never speak to you again!
If it was very very long term bondage, like a whole 24 hours, you will have to dedicate some time to toilet breaks, unless you want your victim to pop his/her bladder.
I would suggest if you cannot be dealing with the untying/tying part, then diaper the victim, you can get adult sized nappies, so just put one of them on.
If you do not wish to use that option then, either untie the victim fully, or tie hands in front of the victim.
But don't ever let them wet themselves or soil themselves while clothed.... Its not pleasant!
