sentences:  Same-sex couples may also engage in non-penetrative sex to preserve virginity, with gay males using it as an alternative to anal penetration.Although sexually transmitted infections (STIs/STDs) such as herpes, HPV, and pubic lice can be transmitted through non-penetrative genital-genital or genital-body sexual activity, non-penetrative sex may be used as a form of safer sex because it is less likely that body fluids (the main source of STI/STD transmission) will be exchanged during the activities, especially with regard to aspects that are exclusively non-penetrative.While non-penetrative sex (or outercourse) is usually defined as excluding sexual penetration, some non-penetrative sex acts can have both non-penetrative and penetrative components and may therefore still be categorized as non-penetrative sex.