Just wondering what you mamas do/did with your LOs when they were tiny?

DS is eleven weeks and we spend a lot of time nursing (supply issues -- he still eats every 1.5-2 hours) and talking to each other, as well as some time under the activity mat and I try to give him at least 15-20 minutes of tummy time a day. Sometimes we go for walks, sometimes there's an errand in there...I just wonder if I'm giving him the right amount of activity and stimulation? We spend a good amount of time just snuggling and talking...