Pumping help

Marcy

I have a spectra s2 pump but I don’t think I’m using it to the point where it’s emptying my breasts. I will pump and milk will spray out of my nipple for a few minutes but then it goes back to just dripping out. I will get about one and a half to two ounces of milk but then if I breastfeed shortly after my son is able to still get a full feed out of one breast. How do I pump more effectively?