Cylindrical thermoses are your best bet.

A cylindrical insulated lunch jar is the best choice if you want something that fits a car cup holder and won’t tip over on a motorcycle.

Most standard car cup holders are about 3 to 3.5 inches across, so look for a food jar or thermos around that diameter. Avoid tall, narrow bottles — they rock and tip the second you hit a bump. A wide-base jar like a Stanley or Hydro Flask food jar sits flat and fits most holders.

For motorcycle duty, same idea: low and wide wins. If you’re bungee-cording it to the passenger seat, a round cylinder with a smooth surface is easier to secure than a boxy lunch bag. Soft-sided lunch bags work too, but they need a top case or a tight strap to keep them from sliding.

If you want one thing that does both, grab a wide-mouth thermos with a sturdy handle. It fits in the car, straps to the bike, and won’t spill soup all over your saddlebags.

Future you will thank you when your lunch is still upright.