It all depends what beverage of choice they're being dunked in.
TEA:
It really is crucial what blend of tea, whether you have milk, whether it's green tea or a herbal etc.
HOT CHOCOLATE:
How much milk, is it real with cream or is it tinned powder and so on and so forth.
COFFEE:
What bean(s), what extraction time, what are you making, sugar? milk?
COGNAC:
Biscuits and cognac.... we won't go there.
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On the whole though:
CUSTARD CREAMS - either but if dry want a drink afterwards
BORBONS - prefereably dunked
HOBNOBS - not dunked, if they're the 'lite' variety bin them
CHOCOLATE HOBNOBS - either but same situation as custard creams
MILK CHOCOLATE DIGESTIVES - normally don't dunk these
PLAIN CDs - dunk and suck or more normally no dunk then bite half off, and place half in mouth to cut off the chocolate in one bite (a god given talent) then eat with the rest!!
DIGESTIVES - dunk, dunk, dunk
RICH TEA - dunked
SHORTBREAD - verging on cakes here but totally dependant on the shortbread
PENGUINS - either (just get rid of the jokes, they seem to have three they permamently repeat)
FINGERS - not dunked
DUCHY ORIGINALS (ANY VARIETY) - not dunked
I'm getting bored now so won't continue! I'm off for a biscuit and cognac now
*/Doesn't raise hand to post 37