Items that are used as examples of something limp:
1) A noodle. (cooked noodles are flexible and droopy)
2) Wet washcloth. (they can be crisp or stiff when dry, but go shapeless in water)
3) Dish rag / rag. (the generic form, also handkerchief, especially if wet as above)
4) Wet leaf. (as above)
5) Hair. (hair that has no body, especially fine, straight, or blonde hairs)
*Bizkit. (the name of the rock band Limp Bizkit is a phallic reference)
Rag doll
simile its a simile when you use "like"
This isn't an idiom. When you see AS___AS___you're dealing with A Simile. This simile is comparing something to a pair of old, patched socks, which would indeed be very limp.
mule
fiddle
As dear as salt
To listen like a hawk.
Niagra Falls morning.
...mule."
as blue as sea
my teacher was as surprised as a dog
This is an example of a simile, as it compares waves to mountains using "as."
nope In order to be a simile, you must have two items being compared using the words "like" or "as". "Sun" is not being compared to anything in your example.