Zardnaar
Legend
I was very clear that I'm talking about when I'm DMing. My ruling is that you are dragging them behind you and that you are basically combining squares if it ever matters. You can't grapple and drag someone while also holding them out at arms length.
Feel free to rule differently, the rules don't go to this level of detail so that different groups can run it differently if they want.
More being called an edge case.
If someone really wanted to muck around with forced movement if the DM was being particularly pedantic why not just build a Sorlock instead? Repelling blast quicker Eldritch blast? 4-6 beams in most games use them to knock opponents wherever.
Edge case being moving in a perfectly straight line. You can force people to move IRL without dragging them. The D&D rules just abstract that.
If they go prone sure drag them more likely just kick them. On the ground is about the last place you want to be btw.