My brother in law fucks my sister but i fuck him

I like my brother-in-law, he is the ideal man to fuck my sister, but the truth is that i have detected that he is a bit bisexual and i want to try it. today i plan to stay alone with him and seduce him, bring my package close to him and pull down his underpants to see if he lets himself be buggered. and damn, yes, the boy knows that i'm going to fuck him well and i've promised him that my sister won't find out how i'm sticking my cock in her and how she likes it...