n: the act of kicking someone while down on the ground, much like the classic "beatdown shot" seen in many pre-bling era rap videos.
Proper alternative usage includes supplanting the word "sneaker" for a particular brand of shoe or sneaker, used at the risk of excessive name-dropping.
1. That dude owes me money, b. Let's give his punk-ass a sneaker massage.
2. That guy tossed my girl, g. Let's give him a Nike massage.