Does it help you watch your tongue? (8)
I believe the answer is:
eyetooth
'tongue?' is the definition.
The answer and definition can be both body parts as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'does it help you watch your' is the wordplay.
I cannot really understand how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
'you' could be 'ye' and 'ye' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for eyetooth that I've seen before include "Yet he too (anag.)" , "Canine in upper jaw" .)