Anal speculum... what next

I did search for this and couldn't find my answer, so...

I'm awfully curious about the anal speculum. I get that it's inserted, spread, locked spread, etc. But -- and yes I did see the video where one inserts cereal and milk -- what happens next? Is it the wide spread it in and of itself (not that being spread that wide and on full display isn't sexy in and of itself)? is there probing/stimulation? Not trying to be naive, but really am at the "okay, now they're spread very, very, very wide... what do you do? stage in trying to understand this interesting fetish.