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To be a little more personal than vouchers for services that you may provide, what about a selection of flavoured and novelty condoms. That'd make a good 'play safe' christmas.

KGB:)

Get some glow in the dark ones, lol. Don't ask how I know about those....
 
talk about it with them but really at most it should be a cheap gift. You are not to the point of spending real chunks of change yet.
 
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