A spread-eagle slampig, or "slammy," for short is a adjective describing a loose woman or man. In other words, someone who is openly sexually active and is usually associated with being dirty. Very easily become sexual prey or is willing to engage in sexual acts with strangers.
I.E. in the military these women or men are considered "moral gear," where anyone willing is able to have a turn.
Example: "I thought that girl was a slut before, but she's been around so much she's more of a spread-eagle slampig!"
Example 2: "I wouldn't be caught in between the sheets with that "slammy", I don't want to contract any diseases.