Look at your bra now. If it's the right size, it should look like this:

1. The strap around your body should be firm but comfortable. When you stand side-on at a mirror, the strap should be horizontal and should not ride up at the back at all.

2. The wires at the front should lie flat against your rib cage and shouldn't dig in, rub or poke out at the front.

3. Your boobs should be enclosed in the cups and you should have a smooth line where the fabric at the top of the cup ends and meets your bust. You shouldn't have any ridges or bulging over the top or sides of the cups, even if you're wearing a balconette or lower cut style.

If your bra is lacking in any of these areas you need to sort it out, and the best way to do this is to get a professional bra fitting. But that can be scary. I mean, who wants to stand topless while some random woman prods at your boobs?

Well, it's really not like that...

This is what happens at a bra fitting. Or at least the one I went to:

1) I arrive at Bravissimo in London's Covent Garden and am greeted by Justina. She takes one look and says she can already tell I'm wearing the wrong bra. She is obv the Yoda of the bra world.

2) We go into a fitting room. I take my sister with me for moral support. Justina tells me that lots of girls choose to bring their mum or friend, which is fine - although it's best to go solo so you can fully concentrate on achieving bra nirvana.

3) I take off my T-shirt and Justina examines my bra. Sounds cringe-worthy, but she's seen it all before and puts me totally at ease. She notices that my bra is on its tightest setting and is still quite saggy and unsupportive.

4) She goes away and brings back a selection of bras that she thinks will be the right size. She knocks on the door before she comes back into the fitting room, so I'm never taken by surprise.

5) It's time to try on a bra. Justina asks if I'd rather she left the room while I do this. She says some people prefer to try on the bras on their own and then get her back in to check the fitting when they're ready.

6) Justina examines the first bra. It's a 32D and she decides that it's too loose.

7) She goes off to get a 30D and gives me a catalogue to look through so I can choose a style I like.

8) Justina fits me with a 30D bra. It's perfect. I practically fall over with shock. She's brought me a selection of bras that she thinks I might like.

9) I start to try on the various bras. Even though they're all 30D, some fit better than others. Justina says that it's important to try on bras before buying and not to assume that you will always fit the same size no matter what.

10) In total I tried on six different bras and left with a 30D that fitted perfectly.

Overall the cringe-factor is minimal, and is far outwieghed by how great it feels to finally be wearing a bra that fits. I feel sleaker, sexier and much more comfortable. Bra-vo for Justina, and hooray for my new boobs!

Get thee to a bra fitting shop now ladies...

...(John Lewis and M&S, among others, do 'em) and let us know the results: slink@bbc.co.uk. Or you could have a go at measuring your own boobs.

Your bra fitting experiences:

I came out at 32 D. I took my old nan in for support =) I was totally at ease and I didnt feel embarrassed, I get mesured now every 6 weeks and I feel a lot more comftable and I get my bras padded to help push the upwards!
Sukie

It was a cool thing to investigate and after I was measured all my friends have been to get measured and we've all grown!! So I started a trend, and now we're all wearing the right bra!!!
Claire x

also obviously our boobs are growing so its important to keep checking that ur still the same bra size!!!
Charlie

i went to have a bra fitting a few weeks ago and was told i was wearing totally the wrong size - i thought i was a 34B turns out i'm a 32DD and i'm only 13!!! The woman who fitted me was really nice and even suggested what types of top i could conceal my large boobs in!!
Sarah