I am no fashion expert believe me but I think it looks sexy when a white shirt is tight around the bust with maybe an extra button open to reveal the cleveage. and UNTUCKED.
Tucking in conjures visions of a bit tomboyish if you ask me.
Outside looks Chavish, unless the shirt is a bit dressy, i.e has a shaped hem, and maybe fitted. Also, if wearing outside, then nipped in t waist with a wide belt is now all the rage.
I personally think a nice fitted shirt, tucked into jeans, (without the blousing over waistbands), looks nice, with a trendy belt around the jeand waistband.
Thanks guys - usually wear tucked in! At least I know I'm not commiting fashion suicide! Might try it outside with a belt around middle. Recently got rid of a linen shirt I didn't think I'd wear again and now I'm regretting it (perhaps it might still be in the charity shop).