“Together, but eyes down: each write the toast you'd give for the other at the next big occasion.”

A set-piece. One table, two pens, the same evening, one joint artefact. These are the pages people photograph.

Why this question

A proper one — one true story, one exaggeration, one line you mean completely.

And once you’ve both answered

Read them aloud to each other. Yes, out loud. That's the price of this page.

Answering it honestly

One table, two pens, the same evening. This one doesn't work by correspondence.
Argue about the details out loud before anything gets written down. The arguing is part of the artefact.
Finish in the sitting. A half-built set-piece has a way of staying half-built.

And the house rule, whatever the mode: leave a blank rather than write a lie. A blank can be filled later; a lie sits in the archive forever, and you both have to live with the paperwork.