The number one reason couples break up is sexual incompatibility...? Jun, who just got a boyfriend, feels anxious about her technique... practice with me (her brother) who she lives with!? 'I don't want my boyfriend to dislike me, so make me practice with you,' she says. From that moment on, an inappropriate relationship between siblings begins! Her sister tries various fellatio techniques she found online, but there's no way I would get hooked on her blowjobs... or so I thought. What started as 'practice' turned into endless licking and pounding...!
