The most common and most likely answer to this crossword clue is the 6 plus 6 letter word WINTER SPORTS
I've seen this crossword clue in The Sunday Telegraph
W
I
N
T
E
R
S
P
O
R
T
S
Buddy explains!
The straight part
We know that "Skiing, and so on" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case skiing, and so on = winter sports.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.