Put on your birthday suit, wrap yourself in a blanket like a burrito, wait for your significant other, friends, or family (if you dare) to see you, and then quickly unwrap your butt-ass-naked-self in front of them, yelling, “Surprise!” You’re naked when you do this - in case you missed it.
Girl 1: Omg, when I got home, my boyfriend gave me a Birthday Burrito Surprise.
Girl 2: What the heck is that?
Girl 1: He was wrapped in a blanket, like a burrito, and then surprised me when he popped out naked!