The most common and most likely answer to this crossword clue is the 6 letter word SIPHON
I've seen this crossword clue in The Daily Telegraph
S
I
P
H
O
N
More clues leading to the result SIPHON
- Drawing device damages iPhone screens
- Drink dispenser on ship at sea
- Draw off Hoylake’s first so pin seen differently
- Drain drink to get title
- Drink, hot, acceptable in tube
- Use of it may weaken the spirit
- Drain drink slowly, darling
- Divert trouble in shop
- Sweet drink is in front of soda dispenser
- Parsi phoneticist soda dispenser
Buddy explains!

The straight part
We know that "tube" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case tube = siphon.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 SIPHON mean?
SIPHON noun- A bent pipe or tube with one end lower than the other, in which hydrostatic pressure exerted due to the force of gravity moves liquid from one reservoir to another.
- A soda siphon.
- A tubelike organ found in animals or elongated cell found in plants.
- To transfer (liquid) by means of a siphon.
- To steal or skim off in small amounts; to embezzle.