Think of a time or place where you felt trapped. Jail? Prison? An elevator? Car breaks down. Stuck on the freeway. Locked out of your house (a reverse trap?).
Write a poem with that in mind. What effect did it have on you? Where did your mind take you? Were other people there and what interactions did you have with them (real or imagined)?
Take a look at an introduction to Reginald Dwayne Betts by Jericho Brown. Both poems as well as the quick introduction to his work.