Brother-in-law masturbated after seeing brother-in-law's hot sex, sister-in-law

Husband wife was lost in hot romantic sex. Wife was in sexy bra panty. Slowly her bra came off. Husband started kissing her back. Then he made her sit in his lap. After some time, wife started sitting on her penis with her back towards husband. Here from the door brother-in-law started secretly watching the hot sex of his brother-in-law. Brother was busy fucking his sister-in-law. But sister-in-law's eyes fell on brother-in-law peeping through the door. Brother was busy fucking sister-in-law. Both of them met their eyes and brother-in-law left from there shyly. Then the next morning brother-in-law brother started masturbating remembering sister-in-law's sex. Meanwhile sister-in-law reached the bathroom and held her penis.