Someone (male or female) that is so bad at sex you may as well be fucking a corpse, although a corpse may sometimes be more lively. These types are usually fairly easy to spot by the lack of personality. They are usually followers
Female dead lays: from beginning to end, she just lays there, no expression or movement, unless it's that of boredom. You may want to check in between to see if she's awake. ;)
Male dead lays: Usually those that are too lazy to put any effort into it. Kinda like a quickie, but with only one person putting any effort into it. Most "nice guys" fit into this category.
a girl thats doesn't moan or scream while having sex. Makes the guy do all the work
The sex was awful she was a dead lay it wore me out.
The same as deadly, but one million times better(see deadly).
Guy: Man that was deadly.
Dude: No, man it was deadlay.
Guy: Ya, you're right, it was that much better.