The TravelMate works—but I give it only about a 2 out of 5. A superior FUD I’d recommend instead is the Sport and Travel Freshette. It’s slightly larger than the TravelMate—just longer than the palm of my hand when collapsed and about half as wide—but still can fit in the hip pocket of a camping backpack quite easily (and you can still use it through your pants’ fly). The Freshette’s larger cup, similar to the unisex collar on the previously reviewed Travel John, fits more easily than the TravelMate—and solves the positioning and overflow problems to which the TravelMate is prone. It really is easy to pee all over yourself with the Travelmate due to its small size and smaller throughput (the main reason I can’t recommend it).
The flexible outlet tube on the Freshette makes for easier aiming. With practice, it’s possible to collapse it after use, store it back in the bag, then get it back out and reuse it without touching any of the wet bits, if you’re squeamish about that sort of thing. And if you need the extra feature, there’s a “complete portable” kit that comes with sealable bags you can attach, in case there’s a need to pack out your waste or you’re going to drive like Lisa Nowak.
While it’s the best product of its kind that I found, the Freshette is more expensive than the TravelMate, and its weird shape and larger size make it harder to pack. Also, the plastic bag it comes with is not the most durable. Mine lasted through about three weeks of camping before getting a hole. Both models tie for ease of being able to clean yourself off without toilet paper.
There are many other variations on the Freshette, which I imagine would work about as well: The Whiz Freedom—quickdry anti-bacterial flexible medical plastic; the SheWee—slightly smaller and available with a durable hard case; the PStyle—more a channel than a funnel and no tube; the Lady J—wider funnel.