When the act of pleasuring one's self goes utterly wrong.
MARK: "I don't think I'll ever be able to face my family again"
DAVE: "Shit, what happened dude?"
MARK: "Well, last night as I was pouring myself a hand-shandy, the cat walked into my room and jumped on my lap, just when I reached my vinegar strokes"
DAVE: "I'm sure he'll get over it"
MARK: "But that's not the worst part; before I could clean him off, my little sister ran in and grabbed him. Later I saw the cat walking around with a mohican while my sister kept saying something about becoming a pet stylist"
DAVE: "Wow. That truly was a masturbatastrophe"
Any material which is worth masturbating to may be referred to as masturbatastic. Pornography, or anyone you would like to see featured in pornography is classed as masturbatastic. 'Wanktastic' is an acceptable variation.
1) This shit is masturbatastic.
2) Your sister is masturbatastic.