On an international red-eye
Step 1: If you're traveling anywhere overseas -- on vacation, for business, to catch an international art thief, whatever -- make it an overnight flight.
Step 2: Since most bigger planes that fly international routes don’t allow for two people in three seats (what with their big center sections and pairs of double seats on each side), the “in-the-seat” option is less likely to work. Request a seat in coach near the mid-cabin restrooms.
Step 3: Wait until the flight attendants start taking their breaks. This is after the FIRST meal service. Again, the cabin lights going out in the front of the plane is your cue.
Step 4: Wait for a lull in business at the mid-cabin restrooms after people start falling asleep. This typically happens around three to four hours into the flight.
Step 5: Once again, nobody cares as much on these flights, so as soon as you see the restrooms are empty, make your move and snag one.
Step 6: Have a long meaningful discussion about your future as a couple in the airplane bathroom. Or, bang each other’s brains out. Your call.