I did this in college, but I just dumped my keeper on some seedlings and burned the leaves. I think it's better to dilute it in water, and water the dirt, not getting any on the actual plant itself. And it would be even BETTER to add it to your compost pile if you have something like that. Then it could break down, and the compost itself could be added to the plant. You can pee on your compost too. Nitrogen rich.
(Not that I've done it, I haven't really. Though wearing ankle length skirts and going commando
would make it really easy....
)