Pumped like a cow over here 
So, if he is feeding from both sides, let him have as much as he wants first and then pump. You may not get a huge amount at first but pumping should stimulate more milk production, in theory.
I used to express more at night, because my DS would often wake up, (or not, we were very lucky) and only have 'one boob' then fall back asleep. So that meant my other boob was enormous and uncomfortable, so I would express to let it down a bit.
Ideally what you want to see in your expressed milk bottle once done is a layer of cream on top - this shows you have expressed the fatty and nutritious 'hind milk' and not just the watery foremilk.
The more you pump, the more milk you make. Drink loads of water, because if you are dehydrated it definitely affects your supply IME.
Take breastfeeding vits too because bfing is quite draining on the body (IMO) and my skin and hair suffered.
Good luck . Hope it works out for you, as an extra bonus you'll probably lose your baby weight quickly (if indeed you have any! )
There are loads of foods you can eat to increase supply, spinach, eggs, avocados ...... Can't remember exactly what else but it's easy to find on google.
If you go to work/out for the evening/etc and leave your baby, make sure you take your breast pump and express at what would be his usual feeding times.