Think of a coloring book, but made of fabric and big enough to cover your lap on the couch. The usual size is close to 59 x 50 inches, and the markers are often included.
You pick a section, color it, and come back to it another evening. Because the blanket is wide, two or three people can work on it at the same time.
Patterns range from flowers and fruit to cats, food or retro game themes. Choosing the design is half the fun, so it is worth looking at the whole pattern before picking.
The part people ask about most is washing. According to manufacturers, washable water-based ink comes out in a normal machine wash, leaving the printed outlines ready for a new round. Always follow the care label on your blanket.
If you want to keep a finished piece, fabric markers with permanent ink are the opposite choice: what you draw with them stays. It helps to decide before you start which parts should be permanent.
Some simple habits make it easier. Work on a table with the fabric pulled flat, and cap each marker as soon as you are done with it. A quick test on an edge shows how strong each color looks on the fabric.
Many adults treat it as a relaxing hobby, something to do with their hands while talking or listening to music. As a gift, it works for people who like crafts but already have plenty of coloring books.