L'Oreal has those Color Juice Sticks, the lipsticks that go along with the lipglosses, I suppose. Anyway, one of them is very much a Lolita type color in my eyes. The same sort of cherry-popsicle stained mouth. I believe the name, fittingly enough, is Cherry Freeze! Very much a sheer and pinkish red.
For a look of stained pinky-red, I also have found success with blotting down any bright red lipstick. NYC's Retro Red is a good one, as well. Can be opaque as all get out, but blotted down resembles a cherry stain. I'd say blotting is the main element in a look like that. You wouldn't want it too bright, and not very glossy at all, either. You'd want it to appear effortless, and resembling a natural flush children often have to their mouths and cheeks, or something of a stain from Kool-Aid or something.
A completely bare mouth also has the connotations that the red stain does. The latest book jacket for Lolita is a macroshot of a totally bare, matte lip.
Aaaand now my creepy allotment for the day is spent. I hope this helps!