Thrust in a circular motion

I keep hearing about having sex using a circular motion when thrusting. What exactly is that and does anybody have any clips of this being performed.
Some girls like it some don't It gives you more friction against the clit. You can also do it when you are completely in her.

Old logic was that this is how small guys got the necessary pressure when fucking, but I have used it with girls that were really tight as a changeup.