Pubic lice -- often colloquially called "crabs" -- and trichomoniasis are STIs that are often also transmitted through casual contact, like by sharing damp towels with someone who has one of those, Stds without having sex or previous relations than just through sexual contact. How can I protect myself from STIs? The Cliff's Notes Be a Blabbermouth! The pill doesn't protect you or your Stds without having sex or previous relations from STIs. There is no risk of becoming infected after exposure to environmental surfaces like door knobs, toilet seats, utensils, drinking glasses, lipsticks, towels, or bed sheets. When it is a regular habit for everyone involved, it's just no big deal -- no more so than other common aspects of sex like having to shift positions now and then because our legs hurt, taking a second to go pee, or asking a partner to change up what they're doing because something else feels better -- nor is it something that gets in the way of trust, intimacy or enjoyable sex.