The most common and most likely answer to this crossword clue is the 2 plus 5 plus 3 plus 2 plus 5 letter word IT TAKES TWO TO TANGO
I've seen this crossword clue in The Times
I
T
T
A
K
E
S
T
W
O
T
O
T
A
N
G
O
More clues leading to the result IT TAKES TWO TO TANGO
Buddy explains!
The straight part
We know that "Responsibility must be shared/why one can't dance" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case responsibility must be shared/why one can't dance = it takes two to tango.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.