The school calendar is out. Wednesday is a half day. Thursday is the meal at your mother's. Friday they usually have. Nobody has named the days yet. Write November 26–28, pickup at 2:00 on Wednesday, return Sunday at 5.
Days. One proposal. Room to counter.
Specific beats "the holiday"
Ask for a decision with the list closed enough to answer: accept this split, or send a counter that names days and times. "What do you want to do for Thanksgiving?" is how November arrives as a shrug.
Write the week as a cold reader would need it:
- each date, who has the child at the start of that date
- pickup door and time
- travel (your mother's, their flight, the Wednesday half day)
- the one constraint that is not negotiable — the meal you already committed to, or the flight they already bought
Your private nickname for them stays off the page. Last December stays off the page. A briefing can carry the week without the eulogy for how the last handoff went.
A sufficient reply is "yes" or a counter with dates. A written no with a different Wednesday is more useful than a paragraph about fairness.
Silence needs a default, then one follow-up
Name what happens if they do not answer. "If I don't hear by the 10th I will keep the usual weekend split and take Wednesday 2:00–Friday 10:00." That is a plan they can interrupt. It is not a threat.
One follow-up restates the proposal and the default. It does not add last December. A third ping is you asking for a call, or you executing the default — pick one.
If the urgency is only your mother's seating chart, say that. It is a real reason. It is not a custody emergency.
Two households can still counter
You approve the send. They need no account — email and a link — unless they already have one, in which case you need an accepted contact. They can reply from the page. A fetched link is not a read. You will not see whether they have told the child.
If they counter, answer the counter as a second decision: accept, or a third map of the same three days. Do not reopen the year.
When the school calendar is sitting in a session and the week is still a shrug, connect your assistant and send the days and one proposal, instead of another December argument in October clothing.