General

Maybe?

I've accidentally conditioned myself to crave food after sex and masturbation, even if I just ate. I've definitely gained some weight because of this

I highly doubt it.

Yes.

You have to wank to get rid of excess testosterone. Keeping that stuff in your body would mean you'd be much more active, aggressive and muscular. Keeping testosterone low increases the hormone ratio towards oestrogen which makes you soft and fat.

You can increase oestrogen by eating peanut butter, especially the one with flax seed in it.