SLPonyPlay - where the ponies meet - your 'hoofbook' for SL ponies

what does full time pony consist of. does it mean that i am a pony all the time? do i sleep in a stable? do i do it all, all the time?

Hi, what it means to be a fulltime pony strongly varies depending on your owner or home sim. Some owners are very strict and take a more animalistic approach, but there's also sims and trainers where it lets the pony a bit more freedoms. 

Full time does mean full time though, so indeed, sleeping in a stall or stable and being a pony Your entire time spent in SL.