What gets your cock to its fullest erection?

This is just a theory: pheromones women release when they're ovulating. One of the few times I measured a full ten inches was with a girlfriend who told me after that she was ovulating. She wasn't on the pill so her biochemistry was au naturel.

Another time it happened was with a woman the night after a wedding reception. I think the whole wedding/reception experience causes a group pheromone release by the ladies present. The reproductive rite of a wedding makes some women broody. I have rarely been to one where I didn't get laid.

Like I say it's just a theory. It's not like I've measured myself in all situations or polled women about their reproductive status at every hook up. Those few events where I did get measured are, well, memorable.
 
1. The right chemistry
2. When the girl says nothing and strips naked rubbing onto me.
3. Also when she ignored my cock, or just gives it a small flick- FUUUUCKKK that drives me fucken crazy.