However, this technique is not without risk of contracting sexually transmitted infections, in particular HIV.
Sexual stimulation of the genitals by using the feet may also be included, and so may manual stimulation of the anus.
Oral sex, for example, which can include oral caress of the genitalia, as well as penile penetration of the mouth or oral penetration of the vagina, may be categorized as non-penetrative sex.
The words penetration and penetrative may be restricted to penile-vaginal penetration, and, in this way, the definition of outercourse additionally includes penetrative anal sex, with the term outercourse used to contrast the term sexual intercourse as vaginal sex.
It might result in one or more of the partners achieving orgasm.
If no bodily fluids are exchanged (as is common), mutual masturbation is a form of safe sex, and greatly reduces the risk of transmission of sexual diseases.