B is a bouncy, boisterous, bubbly letter, sometimes a bit belligerent (biff! bam! bash!), but basically well-behaved.
The b sound is one of the first mastered by infants, which accounts for words such as baby, bebe and bambino, as well the noise they make: babble. In phonetics, it is known as a plosive, since it's created by putting the lips together and forcing air out through them. This is quite a satisfying noise to make, which accounts for the enthusiastic way babies have made it their own.
In terms of phonics, b has a straightforward sound-symbol relationship so is pretty easy to learn. It also figures in two common initial blends (br and bl), and most children also find these quite easy. Keep an eye on pupils who do have trouble with such blends, as this is often a symptom of more profound literacy difficulties.
Watch also for children who have long-term problems in distinguishing between b and its mirror-image, d. Confusion is only to be expected in the early stages which is why most teachers leave the letter b until quite late (by which time the sound and shape of d is well-established). Children then cotton on when helped to see (and feel) the difference in the way the letters are formed in handwriting.
For those who don't, try the bed mnemonic. The child makes a bed shape with fists and thumbs (see picture), which also mimics the orientation of the relevant letters.