Another noob ? My seat turns whenever my uni hits the ground. Wrong size post? Clamp?

I am unsure if this is normal or an issue with wrong size clamp or seatpost?
The seat post does not move when I ride, all my weight on the seat, pedaling, turning, etc, the seat is fine. No side to side, no up and down movement.
But whenever I let the uni fall and hit the ground via learning to dismount, if the handle side hits the ground, the seatpost will turn. Not easily, mind you, I can’t hand turn it back. I have to wedge the wheel and wack with my fist or undo the clamp and reposition & tighten.
I cannot get the clamp any tighter. The ends are touching and the bolt won’t go in anymore than it is. Do I need a shim? Or is the seat going to do that upon hitting the ground?
Obviously, I fall a lot since I am learning and I don’t wanna ruin my new uni.
It has a campy 31.6 to 31.9 clamp. Does this sound right size wise?

What kind of unicycle is it?

what Unicycle frame is it? What seat post? Do you grease your post before inserting (ooer)?

a Kris Holm needs a 31.8 (that is the seat tube diameter not the seat post)

I use single bolt clamps on all my Unis and have never had a seat move on me, not do they clamp all the way up, I still have lots of adjustment left

Most of my older unicycles are chrome-on-chrome in the clamp area. A chrome post into a chrome frame, which is harder for a clamp to hold well. Especially if it’s a cheap-o clamp. We used to tighten those Miyata clamps until they distorted, and sometimes the seat would still twist. So then a little careful filing on the seatpost, and sanding inside the frame, provided a nice boost in friction.

You can try that no-cost solution, but if it’s not enough I recommend getting an exact measurement of your seat post, and seat tube (both are needed for maximum accuracy) and shopping for a strong clamp in that size. Double-bolt clamps are usually very secure, though many single-bolt versions are just as good.

Surly Conundrum 24". The seat post is pretty hard to move without the clamp tightened. So I have a feeling it is that the clamp is too big.
Single bolt.
Good to know it isn’t normal, looks like shim or clamp shopping I go.