During the sweltering summer vacation, I couldn't help but get aroused seeing my sister sleeping with her panties fully exposed! After seeing her sweaty cleavage and crotch...I just couldn't hold back anymore! I rubbed my erect dick against her wet and indented pussy lips, and it slipped in through her panties!? My sister, also feeling good, couldn't help but beg for more. Despite being surprised, I couldn't stop myself and we started having sex, both of us drenched in sweat!
