My daughter was an infant and she was in her crib taking a nap, I heard her start to scream, I could tell instantly by the tone of the scream that something was really wrong, I ran into her room and she had slid her leg in between the slats of her crib and it was stuck way up towards the top of her thigh. It was really stuck and she was screaming and thrashing around trying to get it out, I was scared to death that she would break her leg. I started to panic for a minute trying to decide what to do, the first thing I thought was "lubrication" I thought about cooking oil but it was all the way downstairs and I was afraid to leave her so I looked around her room and I had a bottle of baby oil on her changing table, I dumped it all over her leg and was able to work it out without breaking her leg.
I haven't had to use it since but I'm sure there are many other situations that you could use baby oil or cooking oil to get body parts unstuck, kids love to stick their heads, arm, hand, fingers etc. into places they shouldn't.