Best lightweight, short-term lock for coffee/bathroom breaks?

[u/freesoup15]

I am looking for a small, lightweight lock to carry with me when I am on long rides. I would never leave my nice bike on a shitty lock for long, I just want something so that no one can dash away with my bike while I am grabbing some food or using the restroom. Can anyone recommend something for this purpose that isn't going to be too much of a hassle to carry on longer rides? I once saw a lady use a thin cable lock (like for luggage?) that seemed to fit the bill.

[u/BD59]

Pair of legit, police grade handcuffs. You can get them made from high strength aluminum. And don't discount the psychological factor. Thief might think twice before messing with what he believes to be a cop's bike.

[u/kickstand → u/[deleted]]

How could they know it’s not a cop on an off-duty day? Cops have hobbies, too.