Well, when I think back to school, we used to say "you're pulling my plonker, aren't you?" for "pulling my leg," but in that context I think its role as a sex organ was far from our minds. I think Del-boy's constant use of "plonker" for his brother firmly established the word as non-sexual. On the parks we'd say "you're pulling my pisser, aren't you?"

Come to think of it, when we were discussing "big girl's blouse" the other day for men acting fussily and in a slightly effeminate manner, it brought to mind a slightly less kind expression I learned from the parks men for such a person: "Eee, look at 'im, will yer. I bet he thinks his dick's fer pissin' out of."