Try this
- Keep the essential errand’s timing and workload visible before adding an enjoyable stop.
- Ask at the relevant moment whether the extra still fits. Do not buy or book the addition as if the person already agreed.
A worked example
“After groceries, we could sit outside for one drink.”
An invented example to adapt, not a real exchange or a script you have to follow.
Before you leave it here
Keep the extra stop optional when either person needs to go straight home.