I joined a yoga class and I was the only guy there! I looked around and saw a bunch of girls in tight pants with their butts accentuated by yoga poses! If I had an erection, it would have been obvious and I would have been embarrassed! But the girls who witnessed my erection in an unexpected place started to get horny... and they started to want my dick! I couldn't help but insert it from behind as they invited me, and the girls, whose metabolism had increased from yoga, wriggled their sweaty bodies and came over and over again!