From Wiktionary, the free dictionary
masturb8 (third-person singular simple present masturb8s, present participle masturb8ing, simple past and past participle masturb8ed)
- (Internet slang) Abbreviation of masturbate.
1999 September 23, Ken, “Pants”, in alt.digitiser[1] (Usenet), retrieved 2022-04-14:n e wayz, time 2 masturb8 some more :)
1999 November 9, BennyX, “Free? of course!”, in alt.uk.teens.london[2] (Usenet), retrieved 2022-04-14:Wow your gr8 m8, can I be your m8, we could go ice-sk8ing adn maybe afterwards masturb8 YAY!
2000 September 11, Alec Owen, “Ayn Rand paradigm challenged”, in alt.extropians[3] (Usenet), retrieved 2022-04-14:Yes. In fact a complete excision is preferred. This should stop it from its in8 tendency to masturb8 or self-fell8.
2003 July 21, ci+, “Article on female libido”, in alt.support.shyness[4] (Usenet), retrieved 2022-04-14:I masturb8 only because it's fun to smuck up transom windows :>
2007 April 20, Patio Lemur, “A Skinhead is a Nationalist”, in alt.national[5] (Usenet), retrieved 2022-04-14:Thatll be all the masturb8ing.