What do you think of when you wake up? For most men, even I they aren’t consciously thinking about it their body’s natural state on waking is to be in possession of an erection. It’s therefore difficult to avoid thoughts of sex when that happens.
You don’t have to be having a naughty dream for it to happen so it must be the relaxed state you find yourself in on emerging from sleep.
So do all men immediately think about sex when they wake up or is it more the practical issue of how to safely make a cup of coffee with a big stiff cock waving in front of you?