Wiggles
There are a number of sponsor sites which can fit into several categories. As long as you choose one of the sensible category options for the LL you're submitting to you won't get refused.
The example you gave is a good one and Hardcore is probably the correct cat but if the LL doesn't have that cat (mine doesn't for instance) then you'd have to go with Oral or Blowjob or you could get away with Fetish.
Basically if the Free Site is sound you'll get accepted.
