My drunk sister-in-law, who missed the last train, came to my apartment with her female friend and we decided to sleep in a row! While we were sleeping in a row, my sister's friend's clothes were open, giving me a great view of her breasts and panties! I couldn't bear it any longer and touched her, which made me get an erection. I thought she would notice and get angry, but when she saw my erection, she was in a welcoming mood and started masturbating right next to me. What's more, when my sister-in-law noticed what was going on, she got horny and started masturbating, but she couldn't resist and joined in! We had a threesome!