Holding in feces is not a good idea, When feces is left inside ---- The bowel can become impacted.
The longer you hold your feces in, the more water is absorbed by the large intestine which can cause constipation. This can cause hemorrhoids & become painful. Start moving your bowels when your body requests it to prevent any damage in the future. Also drink plenty of fluids. If this embarrassment is preventing you from regular bowel movements go see your doctor or talk to your Mom.