Adult only. Private by design.
Keeping a lifestyle party off the calendar

Your partner should already know about the night. This page is about everyone else who can see your phone: a coworker, a family calendar, a shared photo album.
The short answer
Do not put the words key party, play party, or the street address on a calendar other people can see. Use a boring title. Keep the address in the host's message, not in a work event. Your partner is not the person you are hiding this from.
Your host invites friends. The host invites friends they'd love to have there. Adult only. Private by design. One private link per couple. If your partner is not invited and does not know, do not go.
Email from the host can say Your event, or a public-safe name they chose. That is a fine calendar title. The street stays back until the host sends it, and even then it does not belong on a shared calendar.
Shared calendars and lock screens
A family calendar, a work calendar, and a couple calendar that shows on a lock screen are three different audiences. Write the event for the least private one that will display it. Dinner out is a boring title. The neighborhood is optional. The street number is not.
If a coworker can see your free/busy time, a blocked evening is enough. They do not need the place name. If a relative scrolls your phone, the title should survive that scroll.
All mutual-yes matches are revealed inside the night, not on a calendar invite. Do not add guests to a calendar event. The host already has the list.
Rideshares, maps, and location
A rideshare app keeps the pickup and the drop-off. If that app is on a shared account or a work phone, the receipt is a leak. Drive yourself, or use an account only you and your partner can open. Do not put the house number in a note field.
Location sharing with family is the same problem. If someone who is not in the room can watch the dot, pause that share for the evening or tell them you are out without the address. Do not use that pause to keep the night from your partner. They should be in the car, or they should already know where you are.
Close the map when you leave. A pin sitting in a recent place is an address. The host can send it again next time. A one-sided yes stays hidden. An old pin does not.
Work mail and photo albums
Do not forward the invite to a work address. Do not say key party in a subject line you would hate a coworker to see. A public-safe name is the one the host already offered.
Photos sync. A camera roll that backs up to a family album will share a hallway, a shoe, a face. The phone rule is still no photos of faces, rooms, or the street number. The morning rule is the same.
A group chat named after the party is a calendar with extra steps. Rename it something dull, or do not make one. Thank the host in a direct note if you want to say thanks.
What still has to be clear
Discretion is not vagueness with your partner. Before you leave home, you should both know the format, the ceiling, and the end time. A key party shows one Play Partner at the same time. A play party reveals matches at check-in. A speed date is short rounds, then yes or no.
The boring calendar title does not change the house rules. You still agree to them before you answer. You can still leave. You can still say no.
If you are the host, send the city page that matches the door and keep the street in the fields until you mean to release it. Guests can put a dull title on their own calendars. They should not have to invent one because the invite already shouted.
FAQ
What should the calendar event be called?
Something boring. Your event, or the public-safe name the host chose, is enough. Leave key party, play party, and the street number off a shared calendar.
Is this about hiding the night from my partner?
No. Your partner should already know. If they are not invited and do not know, do not go. This page is about coworkers, a family calendar, and a shared phone.
What about the rideshare receipt?
It stores the address. Use a car, or an account only you and your partner can see. Do not put the house number in a note.
Can I put the address in the invite I forward?
Do not forward it. The host sends the street when they mean to. Adult only. Private by design. The host invites friends they'd love to have there.
Does a private calendar change the night?
No. All mutual-yes matches are revealed the same way. A dull title does not change the format, the ceiling, or a no.