The happy life of teacher librarians: one use for a ruler

Sometimes at lunchtime, the library will be occupied by a couple of students doing octopus impressions - wrapped up in each other.  In my experience, humour can be vastly effective in solving this, as it generally wrecks the mood and is a more pleasant strategy than a "hands-off" direction.  One useful line is, "Yuck!  Get away from him/her!  You don't know where he/she's been!".  Said of course with a grin - and in deeply appalled and horrified tones.
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There has been one rather persistent octopus couple recently.  They apparently believed that I could not see the back of the library at lunchtime, and so they sat back there with other friends, the two of them glued together.
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So the other day I took sterner measures.  I got out a ruler (a loudly coloured fluorescent one, 12in/30cm) and walked down the back of the library, brandishing the ruler and a cheerful-but-determined expression.  Octopus Couple looked at me with some suspicion, and made a token effort to separate.
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"Nope," I said, "Not good enough.  THIS far apart," and I put the ruler between them.  Now there isn't a specifically stated distance (in centimetres) for students to be apart, but hey, they didn't ask and I wasn't volunteering (the school has a general 'hands-off' policy for all students).  Smiling at them cheerfully, I got them, grinning reluctantly, to separate by the length of the ruler, including moving their chairs apart.  Nearby students were very amused.  Distance established, the ruler and I left that area of the library.
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Five minutes later, (as I had always planned), brandishing the ruler again, I trotted back to that area of the library.  Several metres away, Octopus Couple had spotted me, separated again and said, with all the injured innocence of teenagers caught out, "Look, miss, see?" as they gestured to the 30cm-ish gap between them.  And they smiled, and I smiled,  and the students nearby looked amused too, and the ruler and I went away.
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Five minutes later I just looked at them, from the other end of the library, and caught their eye.  They weren't nearly as glued to each other, and instantly separated, indicating the airspace separating them in a righteous fashion.  I grinned at them, gave them the thumbs-up, and all was well.  (Well, except for the fact that he was now wearing her glasses, and peering about in a rather blind fashion, but that's not behaviour I'm going to fuss with.)
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So you can win with humour, and by being more persistent than they are (I do not, however, underestimate the persistence of the Young Person of Today).  Also, it's amusing.  Part of the happy life of teacher librarians.
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Cheers, Ruth
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