I never thought of this as SI until a few weeks ago. My young daughter (7) has many major health issues and behavioural problems (she was most recently suspended from school 2 weeks ago). With this comes very physical attacks (which often lead to her suspensions, and which took her away from me for 2 years to ensure her younger sister's safety). The bruises etc that I constantly endure from her scare many ppl as they are so bad yet I never stop her doing it to me (usually when she is going to bed at night). I sit on her bed while she does it all to me, (kinda) enjoying it and reminding myself that I deserve it.