After I read your first comment, It thought maybe only one head can experience their sexual organs. Because to my knowledge each head controls and feels different parts of the body. But according to that article they both feel their genitals and orgasm simoultanously. Though I'm still curios how for example bladder control works. Now I wouldn't want to ruin a good existential crisis, but I believe if you apply logic combined with vivid imagination, there is more than enough nightmare fuel left. You never have privacy. Each time you masturbate or have sex you commit incest. According to that article one head can be in the mood while the other isn't, combine that with poor impulse control during puberty and they possibly "raped" each other daily. There is a person who knows **everything** you did during puberty. It propably feels better if the other masturbates you. Imagine touching the nipple on the other half of your body and suddenly your conjoined body has an erection. Or as it relates to this particular case, your twin starts sucking dick and you get an erection. The whole thing is just so incredibly fucked up. Even the non-sexual stuff is weird, like how do you negotiate on which side of your body you sleep? What if one head drools during sleep? I have to stop thinking about this.