I suspect the joke is going over my head too (or between my legs ).
Was this in a British English context? Are you sure about the r?
There was a very successful childrens' book series based on 'the Mr Men'. One of the characters was called Mr Tickle. :: MR. MEN AND LITTLE MISS ::
There was a spin-off series based on characters called 'Little Miss adjective'. 'Little Miss' characters were used in the marketing for dairy-based drinks (yogurt, fromage frais, maybe smoothies too). The joke may have something to do with this. I don't see what though.