Best way to feel it early on (11/12/13weeks) is to have an orgasm. This makes your womb go hard and its easier to feel. Just inform your partner if you aren't trying it solo so they aren't surprised when you stop things to feel your tummy. "Thanks for the O dear. Now I know your mid sex and horny, but before you can finish I just need to have a feel of my tummy to see if I can find my uterus".