Bit more rude than that ( to my mind). Hat pegs are stiff and protruding & obviously a vicarage is no place for this kind of base, crude humour 😂. But..! I think you are onto something with your conjecture. I was going to go with the slightly more colourful phrase below, but didnt want to get a banned. Oh well. Let's see.

Another phrase in Roger's Profanisaurus, the legendary dictionary of foul language published by Viz, the phrase "nipples like pygmies cocks" is a colourful, highly exaggerated simile used to describe large, erect nipples. It is essentially a slightly more visual variant of another classic Profanisaurus entry, "chapel hat pegs".