My son is 3 months and ebf. He eats on demand, approx. every 3-4 hours.

Here's where I'm confused:

He can eat off one side for 10 min, unlatch and be perfectly content and happy and still go 3-4 hrs

Or, he will happily eat another 10 min on the other side and be just as happy and content afterwards and go the same amount of time

I generally try to feed him on the other sides but he seems to spit up more when he eats on both sides

Is he over eating? Hes not gaining weight super quick.

If he only eats for 7 min on one side and idles perfectly content after should I just let him be?