To poke s.o. with a finger; to inject s.o. with a needle; to stick the point of s.t. into s.t.; to poke a hole in s.t.
The -an imp. focuses on the instrument that is being used to inject or poke. The -un imp. focuses on the thing or person being injected or poked.
Why are you fond of poking your companion's side?
Stick that machete in the trunk of a banana tree.
Make the (sharp piece of bamboo) go all the way through that cow's nose when you stick the point in it. (This is done to put a ring in the cow's nose.)