Bra intervention experts - remind me what underarm overspill means?

[Liveinthepresent]

My DH bought me a lovely Fantasie Bra for Xmas - with a little steer from me that I have a lovely 34DD in this brand already. He has bought a Rebecca - so moulded cups which is lovely and I would like to keep but the fit isn't quite right.
I am going to return it today and see if a different size helps but unsure exactly what the issue is - will a bigger cup size help or might it mean this style just isn't so good for me?
TIA for any guidance.

thebetterbracampaign.blogspot.co.uk/p/fitting-advice.html?m=1 - measure according to this to get an idea of the size you need

It generally means that you need a cup size bigger and to scoop, but it could also be that the wires are too narrow for you

Thanks demented I measure 34DD so I think it must be the fact that it's a different style to what I normally choose.
Statistically think you are spot on - having been into the store now I came to the conclusion the wires just don't sit right as 34E was too big at the top of the cup.
Came away with a triumph bra which I think works better - though I associate Triumph as being really middle aged? ... But maybe that irrelevant as I am actually in my 40s.
Thanks for input.

Freya-not the deco,curvy Kate, some fantasie and some bravissimo bras also have wider wires so will be worth a look

Thanks for that - interesting - especially as in the past I found wires on Freya too deep - maybe I am just a weird shape.
Am actually thinking I probably won't spend anymore on underwear for a while as although it feels amazing after pregnancy and BF to wear something lovely and have everything in right place I am hoping to lose weight and guess I may change sizes again.

It's basically a case of trial and error to find the right mid point

Yep the one I bought today would not have made an online basket on looks but actually looks good on.