Adding yolks and whites to, say, spirit and finally drinking (6)

'adding yolks and whites' is the definition.
I can't judge whether this definition defines the answer.

'say spirit and finally drinking' is the wordplay.
'say' becomes 'eg' (both can mean 'for example').
'spirit' becomes 'gin' (alcoholic spirit).
'and' says to put letters next to each other.
'finally' indicates one should take the final letters.
The final letter of 'drinking' is 'g'.
'eg'+'gin'+'g'='EGGING'

'to' is the link.

Can you help me to learn more?