I had a second degree tear, I waited until I wasn't I wasn't sore to "play", but I waited almost 6 weeks because of my tear, but if you feel comfortable go for it at 3-4 weeks, but if you start to get uncomfortable then stop, and if you have bleeding call your doctor. It depends on your tear, if you didn't have one I say easy into it do other things and then try it, but I wait to at least with no tear 2 weeks.
I'm waiting the 6 weeks, because I thought it was the discomfort and things to be worried about, but a nurse at the hospital explained that when the placenta detaches from the uterus, it's technically still an open wound on the inside, and the risk of infection is still there, and apparently not very pleasant. That's why they say to wait the 6 weeks lol