Poo ??
....wee when you laugh, thats just being a female who has given birth, and it doesn't mean bladder cancer.
(or menopausal)
Oh bless your heart, I don't know what to suggest, is it deliberate or accidental or not understanding its hurting you ? I am hoping that you have the support of an autism charity/group ? I think you need some advice on being hurt and how to manage the behaviours. Its not an 'internal organ problem' but you being hurt and in pain is a problem and can't carry on as it is :(