Bundling, say, Roy and Heather together (8)

'bundling say roy' is the definition.
Although both the answer and definition are present participle verbs, I cannot see how they can define each other.

'heather together' is the wordplay.
I cannot really understand how this works, but
'heather' could be 'ling' (synonyms) and 'ling' is located in the answer.
The remaining letters 'hudd' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...

'and' acts as a link.

Can you help me to learn more?