This story from USA Today caused a chuckle or two (HT: Jim Davila). Note, the final comment to the effect that in the end most of the theories about references to genitalia, cross dressing etc are found by the authors to be unconvincing.
However there is one example of this kind of thing that seems to me to pretty pretty secure. That is that the word for feet רַגְלָיו sometimes refers to what we might politely call 'other parts of the (male) anatomy'. The following are among the example where the idea seems to work best:
Exodus 4.25 But Zipporah took a flint and cut off her son’s foreskin, and touched Moses’ feet with it, and said, “Truly you are a bridegroom of blood to me!”
Deuteronomy 11.10 For the land that you are about to enter to occupy is not like the land of Egypt, from which you have come, where you sow your seed and irrigate by foot like a vegetable garden.
Judges 3.24: After he had gone, the servants came. When they saw that the doors of the roof chamber were locked, they thought, “He must be relieving himself (literally 'covering his feet') in the cool chamber.” cf. 1 Sam. 24.3
Ruth 3.7: When Boaz had eaten and drunk, and he was in a contented mood, he went to lie down at the end of the heap of grain. Then she came stealthily and uncovered his feet, and lay down.
2 Samuel 11.8 Then David said to Uriah, “Go down to your house, and wash your feet.” Uriah went out of the king’s house, and there followed him a present from the king.
Isaiah 6.2: Seraphs were in attendance above him; each had six wings: with two they covered their faces, and with two they covered their feet, and with two they flew.
Isaiah 7.20: On that day the Lord will shave with a razor hired beyond the River—with the king of Assyria—the head and the hair of the feet, and it will take off the beard as well.
An equivalent notion is found in the Dead Sea Scrolls (from memory in the Community Rule) where it is usually the 'hand' that is referred to as in 'you must not let your 'hand' stick out through a hole in your garment' - or words to that effect.
Update: Tim is more sceptical than I am about the above (perhaps rightly so in one or two cases). I don't have the time to get into a case by case discussion, but a few comments are in order.
On Deut. 11.10: the point is exactly that the Promised Land will be naturally fertile and thus will not require irrigation by other means (of course the language is symbolic, irrigation is as necessary there as in Egypt in reality). Tim asks 'in Egypt is most irrigation done by peeing?' - well no, but neither is there literal milk and honey flowing in Israel-Palestine, and perhaps good deal more irrigation took place by this means than by carrying water on your foot (images of hopping with a bucket attached anyone?)
Ruth 3.7: Tim asks if my interpretation removes the narratuve tension in the text "did they or didn't they?". He also states that 'there is plenty of other innuendo in the chapter to build up the tension' - I just see 3.7 as a further example of the latter. It does not say 'Boaz went into/knew/lay with Ruth' the point of the euphemism is its very obliqueness.
Isaiah 6.2: I seem to remember that ANE iconography that seems relevant to OT portrayals of heavenly creatures often have the phallus exposed (I have no way of checking this at the moment). Given the well documented Jewish suspicion about nakedness (associated often with paganism), my reading seems to make sense. Feet could mean feet though.
Isaiah 7.20: surely the reference here is to ritual humiliation. Shaving hairy feet would be instead an act of personal grooming!
2 Samuel 11.8: the context here shows that David is trying to get Uriah to sleep with Bathsheba. Now dirty feet might be a barrier to such intimacy, but I thnk a euphemistic reference is much more likely.
Finally, Tim asks "what evidence is there for this conventionally supposed common euphemism?". The DSS provide confirmatory evidence I think, as I suggested. But others might want to weigh in here on one side of the debate or another.
Update: 10.6.08: Tim responds again here. I think we wil, agree to differ. The euphemistic reading makes, for me, better sense of the texts than it does for Tim. I did laugh at his (deliberate) reference to my 'not having a leg to stand on'.!