a) It meets a need for self punishment in me
b) there is something compulsive about it, fulfilling a compulsion can be very satisfying for a while
c) there is also a sort of trance-like state it puts me in that helps me numb myself to other sources of pain (ie the past, the pit of despair) - it's dissociative and yet at the same time also makes me feel real in other ways (NIN got that right)
d) I think there is pleasure mixed in with the pain - it can be like a drug (the endorphin thing) - it's certainly seductive and also like an old lover
e) there is also some self protection in there - if I can take it so far, but no further, it's like control over a deeper suicidal impulse (like it gives it a throttle to pull back on) - but there is also a sense of testing the limits of my urges so it's very much an edge state
f) it's a mark - a symbol - a shared signifier
g) wanting to cut something out, something that feels 'not me' - or reveal something inside, buried, deep

these are all places I go in my paintings now - they provide an alternative channel