But still funny!

Reminded me of another one. What’s the difference between a light and a hard?

 
You can fall asleep with a light on.

Boris was an old, over the hill actor, but due to some contacts he was able to secure a bit part in a local stage play. The play had a sleeping beauty theme wherein Boris had the role of an old woodsman who stumbles upon a beautiful young woman asleep by a lake. He is supposed to make a few short comments and then move on. As Boris finished his lines, the audience broke out into uncontrolled howling laughter, with some yelling and hooting. Boris stumbled off stage confused, where he found the stage manager sitting in a chair holding his face in his hands. “What’s this all about?” asked Boris. The stage manager looked up, shook his head, and slowly responded “Boris, your last line was supposed to be ‘I think I’ll snatch a kiss’.”

They tend to come under the heading of Spoonerisms, a name bestowed because of an British professor who  continually would commit metathesis with his phrases.   For example, he was known to refer to his students as "shining wits"

 
My favorite along these lines is:  What's the difference between a tribe of aborigines and a women's track team?

 
The aborigines are cunning runts.

I suspect you can do the math here.