The first thing you notice about foreign exchange pupils is just how foreign they look. Invariably, their heads were a strange shape, they smelled odd and their clothes ranged from bizarre to hilarious.
Depending on their gullibility and command of English it was occasionally possible to get them to do silly and potentially dangerous things. Most of them were too wise to fall into any trap involving the words fuck, wank, bastard or shit. The skill lay in coming across as trustworthy and in using phrases obscure enough to raise no alarms. We had moderate success with a young French boy who we managed to send into a sweet shop, point to a big jar and say 'clitoris'. The same boy, without any inducement at all, surprised my sister on a cramped car journey by asking if he could come on her legs. She laughed and so did I. My friends decided he wan't a proper French person when he declined the offer of eating a whole raw onion.
On the whole, Germans were more fun becaue it was permissible to punch them for starting wars and gassing people.