Actually, I don't think the Polish sentence could be used in a sexual way, it wouldn't seem natural to me.
Where did the sexual come from? I meant "hat size" (or shoe size etc) as opposed to the size of my entire body.
Having said that I appreciate the knowledge that this doesn't work in a sort of "Carry On" innuendo sense.
"Rozmiar" in general refers to dimensions but also to magnitude, so in theory it could be used with a sexual context, however indeed the secondary meaning seems to be further detached in Polish than in English.
"Rozmiar" has a specific meaning when it refers to a normalised system of fitting, clothing, hats, shoes (though we commonly say "numer buta", literally "shoe number"), rings (jewellery) etc. Since there is no common normalised system for penis size, the connotation is not as straightforward as in English.
I've been observing Euhan1's comments for some time. It seemed like a logical conclusion, and I still think this was actually the hidden meaning ;)