Long stay at a friend's house while on period?

Look to see if they have a trash barrel outside of their house. If so, then wrap the pads up and place them in a bag put the bag in the trash barrel. You could use those plastic bags that come from the stores. If you do use the mothers shower you can always clean it out when you are done. That to me would be an easy solution to your dilemma. Go and have a good time I'm sure your friend and her mom will understand.