Perhaps this is a case of the same word having different meanings in different places. I've only ever punted in Ireland, so I checked the definition in Wikipedia. The first paragaph says
Bareback is a slang term to describe acts of unprotected sex (i.e. sexual penetration without the use of a condom). The origin of the term is by an analogy to riding a horse without a saddle, instead making direct contact with it. Bareback (sex) has recently come to describe all forms of unprotected penetration: anal, oral, and vaginal.