Start with your partner sitting down and you sex positions that are good exercise across his front in a 69 position, Garrison says. This exercise needs a lot of stamina. Get New Year ready with this homemade weight loss drink. Be the first one to comment. Adaptive clothing is a thing now and we are so glad about it! 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.