I recieved a sample of this from Lush many moon ago and it's still going strong to day! That could be because I don't use it all that often but when I do - watch out!
I'm not sure how it comes usually, but for me it came in a plastic tub, which I've since repotted. It's a pale gold color and reminds me of jelly. I haven't noticed any smell with mine, but I could just be used to the tea tree smell.
To apply, I use a cotton bud and dip it into the jelly. It's slightly more hygienic than using my finger, and that way I don't have to touch the pimple either. I swab the gel onto the pimples and leave it to dry - I usually do it just before bed so I don't end up touching it! I don't know if I would repurchase, I'd probably just buy straight tea tree, but it's really nice and while I have it I'll enjoy it.
I used this product for years when I was getting a lot of breakouts. Although this product doesn't always work upon first application, it helped to dry up my pimples and heal them nicely when it was applied a few more times.
I normally use a little pump not too much larger than the blemish itself and let it dry on there. Application at night is better for me, as it does leave a thin dried layer of jelly, so I would wash it off in the morning. Take note to apply on clean, washed and dried skin, as the oils that lie already on the skin make the product hard to treat the blemish and work as intended.
The bottle lasts quite a while, months to years, depending on how often its used and how excessively. A bonus is that it smells nice and is not unpleasant or overpowering!