When performing is not as simple as just not tonguing (or in double bass not bowing) to make it "legato", or that simply shortening the notes produces "staccato". The method of performing legato involves removing all unevenness from each instrument while preserving sonority (even by removing the slur you should still be able to hear the tenuto) and it is very important to keep in mind to "connect the notes smoothly". Also rather than thinking staccato is just "making the notes shorter", try to think that you are "creating a space between the notes". When you play this song it is important to teach these basics correctly (although they are easily misunderstood);and help each student understand them.

-Yo Goto