I have a smaller penis, especially when erect. Is there anything that really works to make it larger? I am tired of my wife's nagging that she can't feel it enough to be satisfied, or wants me to do anal just so she can feel "tight."

Take it from someone with a large penis - size doesn't matter, What I do with my mouth is far more important than what I do with my penis, Study foreplay.

Most all of a woman's feel is on her vulva, primarily the clitoris. Inside of her vagina and up the length of it to the cervix, she can only feel pressure, so size is not really a big factor. Most women can enjoy a small penis as much as a large one. The foreplay and stimulation is the trick. Listen to Im Alec and TubaDawg on this, they are definitely telling the truth.

Size matters, but not enough to not be satisfied. Once you pass the vulva, all we feel is pressure. I'd rather have a man with a small penis than one that is too large.
Foreplay, like Im Alec says, is most important. All those penis enlargement gadgets are hoaxes, so stay away from them.
And maybe, just maybe, your wife needs a little lesson on sensitivity. Like she can nag it to a larger size.
Sheesh! Some people...

She can assist through different positions for you both. This isn't a one sided deal. You came the way you are and she has to accept that. She needs to stow the nagging and work so that you BOTH have an enjoyable experience.

Both of my sisters are married to men with little penis.
Don't ask how I know. Both sisters have confided that they like it in the butt, so they know when it is in.

my brother, i dont think the problem is with your penis, but psyc. I dont think she is the only girl u ever slept with but certainly the only who complains... Think!

It is not possible to make the penis larger. The anal thing is your decision. But size does not matter, being able to control the penis matters. Study foreplay, and don't forget that the nerves are 1 inch in the vagina. So if your penis is more than 1 inch, then you can satisfy your partner. Practice; practice makes perfect.

Shave your pubes, lose weight, and possibly use an extension or strap on. Your wife can try kegel exercise to tighten her vagina if it is too loose.