Masturbation is kind of like loshon horah, both are terrible sins and everyone is doing it pretty often. Typically when someone wants to find out if you’re frum, they ask if you keep kosher and shabbos, if you masturbate on shabbos you are mechalel shabbos and aren’t frum, but if you masturbate during the week it’s cool, you only get kurase cut off, of the ex communicated variety, don’t worry your penis will remain intact, although according to the Light of Efraim* you will be chased through the skies by all the semen you killed and then you will be boiled in your semen. How on earth our neshamas without their bodies can be boiled is beyond me, but I don’t want to find out.
I know you thought this was all a big joke, so if you want to remain ignorant and go on breaking shabbos pretending that yanking your kishke is a mitzvah because it relaxes you and you are supposed to feel good on shabbos – read no further.
The following is a direct quote from the Ribiat sefer on 39 melochos:
“Very gentle massaging to relax ones muscles, or to alleviate muscular pains, can be permitted on shabbos. As explained, strenuous or vigorous exercises are forbidden. Mildly rubbing and manipulating the muscles is not halachically considered medical therapy. However vigorous rubbing and massaging should not be done on shabbos.”
Source: Pg 499, vol-2, 39 melochos, Ribiat
How about that for some koveah ittim?
*The Light of Efraim has got to be one of the strangest books I have ever read. It is about a young couple becoming frum and dealing with their sexual improprieties from their former and current lifestyle. The guy who wrote the book is a kabalist and if you feel like reading about boiling in your own semen, and all of the other good stuff that is going to happen to you if you waste your seed and have premarital sex, or don’t go to the mikvah I would suggest checking it out. If you want an interesting Kabbalah read – this may be a bit much for the Kabbalah center type.