A motion, action, or movement containing qualities or similarities to the act of masturbation or otherwise masturbative properties.
1. He moved his hand up and down rapidly in a masturbatastic motion.
2. She wiggled her fingers masturbatastically at me.
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.