I assume(not having heard this song sung in rugby context) that we have a simple Pavlov's dogs effect here. Apparently the song is often sung in these social circles. So if the general entertainment of the evening is good old Rugby smut, anything regularly included in the bill of fare will produce the same salivatory response. Especially as the word "virginity" is included in the song, which will be the key "bell-ringing" signal to the Rugby enthusiasts: aha, filth, let's all snigger. Remember, we are dealing with a group of people, of whom a significant proportion will have suffered from regular hard blows to the head over a long period of time. We can expect their herd behaviour to be a little on the dribbly side.