A phenomenon that takes place in the popular areas of a big city (like in Miami, this would consist of South Beach, Coconut Grove, Coral Gables, Sunset Place and Downtown), usually on a Friday and Saturday night, the nights where lots of people go out. Consists of riding around in a hooked up car (body work, rims, etc..) but most importantly is the presence of a sound system with bass inside of your car. It is preferable to have your car filled with your "boys" showing you are all in on it. Your music needs to be playing loud and your windows down. A rattling car from bass typically always attracts people's attention for a moment, and then they go on their way. One of the rare cases that traffic is a good thing because with more traffic comes more time to show off. Rap is the music of choice during a loser lap due to low bass hits and the intensity of the music. You can take the approach where you look serious and tough and let the music do the talking for you or you can play around more and cat call at women in addition to the music playing. Once you have travelled past the popular area, you can turn around and do it again (thus the concept of a lap) because people are always on the move and you will have new batch to show off in front of. Or you can go to a new area. The concept stems from the animal kingdom, similar to how a lion flaunts it's mane when it wants to show off and reproduce. The ills of loser laps can't be elaborated on enough. The modifications to your car will costs hundreds, if not thousands of dollars. Women don't respond sexually to bass rattling a car and your cat calls. The attention that you get is fleeting and will leave you feeling empty as soon it is over increasing the need to do it again. And it is not a substitute for actually approaching a women in person and carrying on conversation. Typically performed by adolescent men who are insecure about themselves, don't have enough courage to approach a woman, and subscribe to the "thug" subculture (thus the concept of the loser). Also note that this behavior can result in a citation from police for noise violation.
Yo dawg, it's Friday night. Let's go to Coconut Grove (The person will not explicity say let's go do loser laps. It's just what they intend to do when they get to Coconut Grove, assuming they fit all the criteria mentioned above)