I laughed when I read the title, so ridiculous asking that. well, the advice is be ready to defend (if the situation permit) or just get down with racket protecting your head always racket up and pointing the shuttle.
[MENTION=118495]opikbidin[/MENTION] I don't think this is ridiculous question at all. On the contrary, the experience can be quite frustrating. And suggesting "racket up" in a defensive situation is not good technique. [MENTION=123190]hidroyn[/MENTION] First of all, check your positioning. When the opponents smash, you should stand at about the center of the court (side-by-side in doubles and mixed). You may want to go a little more to the back so that you have more time to take the shuttle. If it goes towards your head and you are standing in the middle of the court, it's most certainly out though, so simply ducking/moving away works too. If you find yourself in the front of the court and unable to move back in time, simply put your racket up in front of your face, and/or duck behind the net. Afterwards, make sure to analyze how you can improve your tactics and technique (with a coach or experienced player) in order to determine what went wrong in the rally - after all, you should be the one smashing!
Depending on his smash, sometimes you can lower your body enough and racket up to block/drive the shuttle back with forehand. Of course, get ready for it first, physically and mentally.
OK seriously. You need to work on your defence and reaction times. I will often tempt people to smash at me because I am very confident in my reactions and can often produce a winning response before the person has had time to recover from their smash (obviously each opponent is different and you alter your tactics to suit). Try a bit of cross training to improve your reaction speed. Speedball work, perhaps, to improve your ability to swerve and counter hit. You could also get someone to feed you shuttles in smashes and pushes to your body and head so that you can practice your defence away from the game environment.
Err.. If your getting hit in the forehead then your in the wrong place. Phihag's pretty much covered it in his post, But. . . . As a daft question. Are you female & playing mixed doubles? If you are and your partner is telling you to stay at the front then dump him & find someone who knows how to play mixed properly. Odds are he's telling you to stay at the front & then playing half court clears & thinking he's playing well. . . .