Sid doesn't know that Alex sleeps around. It's not something you talk about on the first date. Who else he's fucking isn't his business yet, he just wants some sex for himself. Alex doesn't care what hole he lets him stick it in, just so long as he gets the chance to get his cock wet. He starts by getting Sid to bend over so he can spread that ass and lick it wet, then gets some toys out and starts reaming it out wide enough to take his cock. Once he's almost there, he jams his cock in Sid's mouth.