What licensing do you need to sell hookah services not the tobacco itself ?

I live in a very small town and the bar owners let me bring my hookah on certain nights to smoke and karaoke well I've got a lot of people wanting to smoke too so i got some disposable tip covers. It's been getting kind of expensive sharing with the whole bar so I thought for a minimal charge I could pay for the tip covers and buy more flavored tobacco? but I don't want to get in trouble me or the bar etc.. So I was just curious since I have already paid tax on the tobacco when I purchased it is there any thing illegal in my charging them a little, and what might I do to cover all the bases to do things properly?