Tony -

He spelt it out in fireworks for you and got down on one knee at the top of Stark tower

Steve -

Was all romantic and laid out flower petals on you bed spelling out the question

Clint -

Took you out on a date to your favourite restaurant and got down on one knee before desert

Bruce -

you went travelling together and were in London on the London Eye. When you stopped at the top, he was on one knee proposing

Thor -

Took you to the Royal Asgardian flower garden and you saw your favourite flowers planted in the middle. The flower in the center held a delicate diamond ring which Thor placed on your finger once you had said yes

Loki -

You loved waking up to Loki as it was the only time he was peaceful looking. You ran your fingers lightly over his face and he awoke at your touch

'Good morning Loki'

'Good morning my love, I love you' he said which made you suspicious

'Hmmm, what do you want Loki?'

'You to marry me?' he replied which caught you completely off guard