JO buddy
A guy you regularly jerk off with: JO stands for jerk off, and the arrangement is casual, friendly and usually hands only.

A JO buddy is a guy you jerk off with. JO stands for jerk off, or jack off, and the buddy part is the important one: this is a regular arrangement, usually casual and friendly, where two men get together to watch porn, stroke, maybe lend a hand, and go home. No dates, often no kissing, rarely anything more.
It is the friendliest setup in gay sex. A JO buddy is not quite a fuck buddy, since penetration is usually off the table, and not quite a friend, since the friendship has a very specific purpose. Many men have one for years.
Where it comes from
JO is a straightforward abbreviation of jerk-off and jack off. Green's Dictionary of Slang finds it in Bruce Rodgers' 1972 dictionary of gay slang, The Queens' Vernacular, in a definition of two men masturbating each other. The combination JO buddy grew out of that, alongside JO parties and JO clubs,; nobody has dated the exact phrase.
Who looks for one
JO buddies are popular with several kinds of men. Side guys, who do not do anal, often build their sex life around it. Men in relationships with rules sometimes have a JO buddy because "hands only" is what their partner agreed to. Bi-curious and DL men often start here, because jerking off next to another guy feels less like crossing a line, and the phrase "just JO" in a discreet profile is a familiar signal. And plenty of gay men simply like it: it is easy, low-pressure and fun.
The JO buddy also has a group version, the circle jerk, and a near synonym for the one-on-one act, mutual. If the buddies get closer and start rubbing cocks together, they have moved on to frot.
How it is used today
On the apps, JO is a tag and a filter, and "JO buddy" is a common thing to be looking for. The details are usually spelled out: porn or not, hands-on or hands-off, cam or in person. Cam JO, jerking off together over video, has its own large following, for men who like company but not the commute.
Jerking off together is one of the lowest-risk things two men can do, which is part of its appeal. A JO buddy is low-drama sex, and that is the whole point.
Related terms
Sources 1
- Green, Jonathon. "j.o., n." Green's Dictionary of Slang, online edition. https://greensdictofslang.com/entry/5cj4wpy