I bought a really cheap, but amazing retractable lipbrush from Walmart and thats all I ever use in it. Its tiny so it slips in my purse, and since theres a cap on it it doesnt get al that crap stuck to it.
sometimes it's annoying to carry around the tlc's so what i do is i stick my retractable lip brush and put a glob on in the morning and then put the cap on. during the day, i just pop my brush open and there's already enough lip conditioner to last me a couple applications/touchups. just a thought... b/c my purse is flat and the tlc looks bulky in it. so i dont carry it with me.. it's like a make shift lipstick!
I use my finger only if I have just washed my hands (which is stupid because I wash them again straight after...duh). Outdoors I wouldn't dream of doing that.
I don't like it that my retractable lip brush doesn't have a cover as such, so I like to carry cotton tipped buds in a small ziplock bag and put it in the small pocket of my bag. You could technically cut them in half so as not to waste the other tip. But you'd need decent ones that don't leave fluff on your lips.