CrimsonKidCK:
Ahhhh well, the letter "B" is also the most common first one in describing a spankophile's target area--bottom, behind, buttocks, butt, backside, bum, buns, etc.--all of which alliterate with "bare," of course.
The letter "S" is likely the most common first one in describing what's done to that target area--spanking, slapping, smacking, striking, strapping, switching, etc.--and also possibly in describing the sensation produced on the target area--stinging, smarting, sizzling, searing, scorching, etc.
But you'd have to explain why spankos who choose S names are less likely to write stories than ones who choose B names. Any number of puns suppressed here, including Hamlet and existential philosophy related ones.
About "Barretthunter" - it comes from a real person's surname, Barrett.