The room was so hot that my sister's friend was wearing very thin clothes, and I got a full erection! My sister brought her friend home for summer vacation, but the air conditioner in the room broke, and it became like a greenhouse! The fan didn't cool her down at all, and she was still covered in sweat, so she took off her jacket and flipped up her skirt, exposing her panties and nipples! Seeing her like that...