Disco Biscuit, out of all the Butter London polishes is that one I have wanted the most. This is because of two reasons, because it's pink - and because I think the name is hilarious. I've finally managed to get my hands on it when ozsale had a BL sale!
The formula is a raspberry pink jelly with micro glitter. I applied four coats, because it really needs to be built up. The first coat, is sheer and gritty - the more coats you apply, it smooths out. I applied SV over this which obviously makes it even smoother.
So, I like the polish.. BUT - it left a hideous red stain on my nails. My nails at the moment, look sunburnt. Apart from that, it is nice looking polish. I find the Butter London's need your patience when being applied. I'm not really a fan of sitting there for ages painting and waiting - although sometimes that is inevitable. But I find the formula to be slow, sheer and gritty on all BL's - BUT with patience they do turn out lovely. I say this from my own experience obviously, and with all the BL's that I own (check out 'My Stash' to see which ones I have).