"coming out of the cupboard" is a term to decribe the act performed by claustrophile glory-hole fetishists.
The participant enters a cupboard and sticks his manhood through the glory hole for a happy ending.
Al: "I think a seagull just shat on me in the kitchen"
Jon: "No, that's just Roy, coming out of the cupboard. Do you see the glory hole drilled in it?"