Curious George,

This is a frequently asked question, for sure.  And the answer may require some people to go look at kittens instead.

My general rule in answering these questions is to ask the person asking the question to flip the script.  That is to say, reverse the question and ask it of yourself.  So, let’s try that here.  I’m assuming that you’re a straight woman, or that you prefer sex with a man.  That said:

If straight women like penetration with a penis, why don’t they like penetration by a dildo – from a woman?

As you’ve identified, there is a difference between the two.  Your preference is for a penis.  My preference is for a dildo.  And for a woman.  That’s all.  It’s not that I don’t like penetration.  It’s that I like sex with a  woman, and everything that comes with it.