Eat unda sheet - When you're getting deep-throated by someone's tongue like i

When you're getting deep-throated by someone's tongue like it's a vacuum cleaner and you're the sock.

My brother said he ate unda sheet and his mom came in and yelled, 'What's that noise?'

I ate unda sheet so fast, my face turned red like a tomato that got stepped on.

My friend said he ate unda sheet and now he can't stop burping.