None of my clients have used maca. However, some have had good results with saw palmetto. There is an excellent book that goes into detail about all of these options called "Natural Solutions for Sexual Dysfunction" by Dr. Howard Peiper. It's important to have medical supervision when using herbs because they have medicinal effects. Some herbs, for example, are not appropriate if you have high blood pressure or other conditions. I worked with a 65 year old client who healed his sexual dysfunction with tantric practices. This could be another viable option for you.

Melissa

I've used Maca, and it is fine. (It's actually not an herb, but a cruciferous vegetable from Peru.)
Another really swell thing I've recommended is the amino acid Arginine, but be sure to look for arginine pyroglutamate, which is supposed to be 10 times more potent than regular arginine, or arginine hcl. This works best when taken with a multiple B, and if you wash these down with apple or cranberry juice (or both!) about 45 minutes before a session, you'll become a believer.
This arginine, BTW, doesn't nullify any lysine you may take, and in fact often comes bundled with it. The only side effect I'ver ever read about is apparently from an isolated incident in China years ago, when megadoses of arginine amped up a herpes virus cold sore...
Some people also enjoy the amino acid Tyrosine as an additional "feel good" item. As usual, check with your local health food store chaps, and even a health care person that believes in this "alternate" stuff...

Regards
J