I felt them!!!!!!!
This happened to me just now!! I'm almost 13 weeks with twins. While pushing down with the doppler wand to hear the heartbeats, I can always hear them moving around. They sound kind of like loud "BLOOP"s! Well, at one point I heard a loud bloop and FELT it down there. It made me jump and it took my breath away! It was amazing! I didn't feel it again after, but I know what I felt!! I am very surprised at how strong it was. Maybe they both did a flip simultaneously and having the wand pushed down made me be able to feel it, haaaa ?.
It was so incredible! I am so in love with these miracles!