This is a true story I could be made up (but it could very well be a made up story that could be true).
A neighbour couple's son walked in on them while they were 'cooking up a storm,' or 'peeling the banana,' or 'tying down the boat.' Now perhaps they were doing literally that (I wan't there so I don't know), i.e 'cooking up a storm' for a big dinner party, or 'peeling the banana' to put in their cornflakes, or 'tying down the boat' since a storm was moving in... but you, the reader, probably jumped to a conclusion and made a fairly broad assumption about what they might actually have been occupied with.
A neighbour couple's son walked in on them while they were 'cooking up a storm,' or 'peeling the banana,' or 'tying down the boat.' Now perhaps they were doing literally that (I wan't there so I don't know), i.e 'cooking up a storm' for a big dinner party, or 'peeling the banana' to put in their cornflakes, or 'tying down the boat' since a storm was moving in... but you, the reader, probably jumped to a conclusion and made a fairly broad assumption about what they might actually have been occupied with.