... although chap's not attractive if he does it? (9)

'he does it?' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'although chap's not attractive' is the wordplay.
I cannot quite see how this works, but
'chap's' could be 'mans' (chap can mean a man) and 'mans' is located in the answer.
'not attractive' could be 'plain' (I've seen this before) and 'plain' is located in the answer.
No letters remain.
This explanation may well be incorrect...

'if' is the link.

Can you help me to learn more?