Is this even finished? You said it yourself, the quality of it makes you cringe. Why would you post it here if you knew it was bad?
If you want to get better at drawing, don't start with porn. Go and practice the basics: shape and form, basic anatomy and proportions, line control, etc. There are resources all over the internet for that kind of stuff, I'll even link one for you - http://www.squidoo.com/how-to-draw-learn
And in the future, responding to negativity with more negativity isn't going to help you or anyone else. Listen to criticism and improve. It just takes patience and commitment.