the seat post is slipping a bit, which is annoying.
If you mean the seatpost collar: It's pretty hard to get those tight enough. If you don't need the QR function, I highly recommend replacing it with a standard one. Otherwise a good set of pliers does wonders.
If you mean the seatpost clamp: You can try pulling it apart and applying some fibergrip to the contacting faces, but it's a toss up as to whether or not it will help once it starts slipping.
If you mean the seatpost collar: It's pretty hard to get those tight enough. If you don't need the QR function, I highly recommend replacing it with a standard one. Otherwise a good set of pliers does wonders.
If you mean the seatpost clamp: You can try pulling it apart and applying some fibergrip to the contacting faces, but it's a toss up as to whether or not it will help once it starts slipping.