The bend is a characteristic element of the blues. It is a technique used to extract more notes than those that are naturally available on the harmonica just by blowing and drawing. In practice: The bend will always be in the “Uh” vowel sound. So in the vowel sound "Ah" the throat muscle is relaxed, in the "Uh" sound, the muscle is contracted and you will draw with more pressure. And that will make the note come out lower. Repeat and practice as many times as you need, it is important to have enough patience to find the sound of the bend (in fact, it takes more patience for the bend, than for that first moment when you were playing isolated notes). Concentrate on the movements that happen with your throat and the base of the tongue, when making this vowel sound transition, after all, just the shape of the “Uh” in the mouth is not enough, we have to change the air pressure that will pass through the harmonica.