They don't. Skeletons don't have lips, they just bone.
Because it had nobody to go with.
He had no body to go with!
Because you can't bury them in trees!
He didn't have any *body* to go with But he still really wanted to bone.
S'cuse me, while I kiss the sky...*
They give a peck to the cheek.
Their lips are moving.
They're the ones with stretch marks around their lips.