The problem with being a genius (a supergenius) is that Rodney remembers things really well. Things like John's mouth, moist like he'd licked it when sweat beaded on his upper lip. Also things like John's tongue, which Rodney really hadn't seen but can imagine very clearly, licking salt water away.

And John's stubble, which would be rough against Rodney's thighs, and John's breath, which would be warm.