I'm curious if guys are hard when they start sex (women answer "Is your current partner hard when they start sex.") When I take my clothes off to start foreplay with my girlfriend I'm usually still soft (although I feel "horny"). It's not until she starts touching me or I actually take a look at her nude that I start firming up. Same thing with masturbation; unless I've been looking at porn I have to take a few minutes rubbing my balls and nipples before I'm hard enough to start jacking.
It's funny how some guys take a bit of warming up to get hard, while others are hard right away. I suppose female arousal is kinda the same