Slim-fit pants or skinny jeans have a snug fit through the legs and end in a small leg opening. Other names for this style include carrot leg pants, cigarette pants, drainpipes, peg leg pants, pencil pants, skinny pants, slimjims, tapered pants, old-school hood jeans or ice-cream cone pants.
en.wikipedia.org/wiki/Skinny_jeans

ål i strømperne = folder i strømperne fordi de er drejet om benet eller er gledet ned. (Nudansk Ordbog)

Go to page 3 of the below source

In the old days stockings used to be ´ålede´when they stretched and wrinkled at the ankles and knees during the day´s wear.

Possibly these would be generously long and wrinkled at the ankles too - I would not know! But tight pants need to give or wrinkle somehow to make it possible to sit down or bend at the knee.

Nudansk Ordbog -

ål 1: fisk...
2. (overf.) folder af strømper; strømperne hænger i ål


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Note added at 12 hrs (2008-11-27 08:14:44 GMT)
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Another possibility is something like slinky, if the ´ålede´means ´ålenslank´

Actually, I searched for 'puckered' at first, but now I'm pretty sure this is what you're looking for. Check out the links - the term is often used in relation to 'skinny jeans'. For once, the sites include some excellent pictures :-)