poseći

1. (with se) to cut oneself
   Posekla sam se na nož dok sam sekla hleb. — I cut myself on the knife while slicing bread.
   Pazi, da se ne posečeš na staklo! — Careful, don't cut yourself on the glass!
2. (a body part) to cut
   Posekao je prst dok se brijao. — He cut his finger while shaving.
3. (of trees) to cut down; to fell
   Posekli su stare topole pored reke. — They cut down the old poplars by the river.

To cut oneself on something is poseći se na + acc.: posekao se na staklo.