Offhand: Do it in writing, or over short video seem excellent for many versions of this.

Have a lawyer write it.

If you are prone to dissociate, this might be a time to use that.

Keep it short, avoid pauses and vague subjective wording.

Schedule something you need to get to shortly after.

Communicate at a large distance or from across a closed door. (Less good, rarely correct, use a blindfold.)

Spend time practicing observing feelings and letting them pass without effecting you, try to notice when tears are coming early.

Edit: how could I forget!?! Lithium. Needs a prescription and a few days though.