Have you ever heard of Traumatic Masturbatory Syndrome? Me neither, maybe you suffer from it but don't even realise. Traumatic Masturbatory Syndrome (TMS) is the habit of masturbating prone. It causes severe sexual dysfunction in most males who practice it. In other words, if you develop a habit of wanking face down, it will fuck up your sex life.....for ever!
''Some TMS practitioners rub their penises against the mattress, pillow, or other bedding, while others thrust into their hand. Some rub against the floor. Masturbating face-down puts excessive pressure on the penis, and especially on the base of the penis. These sensations are not easily replicated in conventional masturbation or in sexual intercourse. This can make TMS practitioners unable to have normal sexual relations. Apparently according to some survey males who masturbate conventionally have sex 6.6 times more often than TMS practitioners.
The most common problems TMS sufferers have are inorgasmia (also called anorgasmia; it's the inability to have an orgasm during intercourse); or delayed orgasm. Many TMS sufferers also have trouble getting erections. It's a common experience among males who are used to masturbating face-down to engage in sexual intercourse for over half an hour, fail to have an orgasm, and then try to reach orgasm in an atypical (and usually unenjoyable) way, such as thrusting the penis against his partner's legs, palm, or bed. Needless to say, the female partners of these men find their behavior unusual and disturbing. These women often wonder if they are to blame for the man's inability to reach orgasm through intercourse.''
So next time you're rubbing yourself off against your nan's sofa, stop and consider the implications of your actions. According to this website, you may well be fucking your dick up for life.