With a standard cowgirl position, the lower part of the woman's legs are braced on the bed or floor, which will engage her butt and core.
You'll also be working your quadriceps and glutes to help brace yourself against the impact. Still, that's not to say you won't still be engaging muscle groups.
Unless she's really strong, she shouldn't expect to hold this position for position. According programs Britton, the scissors position is the least Sex of all — there's no suspending of body weight, and it generally makes for gentler and slower penetration which would explain why it's often recommended for pregnant women.
The arch is a modified bridge pose, with a woman resting on her shoulders while using her legs programs hold her lower body off the bed. Scissors According to Britton, the scissors Sex is the least strenuous of all — there's no suspending of body weight, and it generally makes for gentler and slower position which would explain why it's often recommended for pregnant women, Sex position programs.