Originally in PK, reported in HolQeD 3:2 p. 10.

(HQ 10.2:10-11):  roS "use the third toe" is phonetically identical to roS "lick" as well as the roS found in roSHa'moH "paralyze".  The verb for paralyze consists of three elements: the verb roS (of unclear meaning), -Ha' undo, -moH cause.  Thus it may be literally translated as "cause to no longer roS" or "cause to un-roS" or the like.  A verb roS having anything to do with general mobility does not occur except in roSHa'moH.  If the toe verb roS is the same verb, paralyze means cause to not use the third toe.  Perhaps mobility of the third toe was associated somehow with mobility in general.  Indeed, there is an idiomatic expression pe'vIl roS "he/she uses his/her third toe forcefully" which conveys the idea that he or she is particularly agile or nimble or spry.  On the other hand, maybe the motions of the Klingon third toe look like a tongue licking.