The most common and most likely answer to this crossword clue is the 8 letter word PLUGHOLE
I've seen this crossword clue in The Times
P
L
U
G
H
O
L
E
More clues leading to the result PLUGHOLE
Buddy explains!
The straight part
We know that "something that can be draining" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case something that can be draining = plughole.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.
What does PLUGHOLE mean?
PLUGHOLE noun- The hole at the bottom of a bath, sink or tub, which can be blocked using a plug; a drain (US)