Set up memes

I'm trying to come up with a set-up for an amputee joke, but I'm stumped.

So why don’t blind people go sky diving? It scares the hell out of their seeing eye dog.

When does a blind person know when he’s about to hit the ground? The leash goes slack.

As a son, I set up a home date with my mom and my friend because I was going out of town. I set it up by telling my friend that my mom thinks he is cute, and I told my mom that my friend thinks that she is hot.

I came home the next day. I see in the living room my friend giving it to my mom doggy style. I ask what's going on. My mom said to me, "Meet your new daddy," then my friend said, "Hey son, get me a beer from the fridge."