There is not enough description to give a good response.
Are the attacker and I alone?
Who is the attacker to me?
Why is he poking me?
Do I have room to move around?
Are we all to make up a whole scenario start to finish and give responses to actions and reactions along the way?
Here goes my made up/dream scenario,lol.
If he pokes me and threatens me and I have no way to move ,I would try to deescalate,raise my hands as if a form of submission,try to talk him into stopping his threats and physical actions.
If he continues and or seems to move up to the potential for the next level,I would reach to his poking hand,grab his finger with one hand and his hand/wrist with the other and turn his hand and finger into a joy stick and base,bend it back while pulling the base and arm out and down, take him down,or snap it.
If he does not go down from the pain and he allows me to break his finger then,I would,move to an outside angle of attack,chop into his bicep,add a forearm/elbow strike across his chest rising to his chin,shove his head up and back from underneath as I sweep his closest leg out,forward.
Then I could get away/run,or since i still have hold of his hand,if I was a law enforcemnet officer, I could roll him to his stomach and cuff him.
One multiple response to one partial scenario.
But we do not know who we are or he is so this is all speculation,lol.