Being asked to deliver a few words on behalf of the bride and groom is flattering, exciting — and utterly unnerving. For one, it's public speaking. Add to that the pressure of executing a poignant and witty speech — without bawling, shaking or, ahem, slurring.

Here's what experts have to say about do's and don'ts:

STAY SOBER: "I had one wedding where the bridesmaids, after quite a few drinks, got up and started telling stories about the bride that were really inappropriate," says Laura Weatherly, owner of Engaging Affairs, an Alexandria, Va.-based wedding planning service. "It pretty much ruined the wedding."

GAUGE YOUR AUDIENCE: Since wedding receptions are usually less intimate than bachelor parties, showers and rehearsal dinners, tailor your toast to appeal to a broader audience.

POKE FUN, CAREFULLY: Though many experts say it's helpful to open with something lighthearted and funny, humor is tricky. "Until you've really practiced speaking, it can fall flat," says Steve McCardell, owner of www.Yourspeechwriter.com. Whatever you do, make sure the humor isn't insulting.

SHORT IS SWEET: It's great if you have a lot to say about the bride and groom, but save it for another day. A reception is a party, and people want to eat, drink and dance. McElwain says most toasts should be no more than three minutes or roughly 500 words.Pages of prepared text will elicit groans.

KEEP IT PERSONAL: The best toasts help the audience understand your relationship with the newlyweds as well as their relationship with each other.

Carol Marino, owner of A Perfect Wedding in Fairfax, Va., says her favorite toast was one in which the best man spoke of a trip he and the groom had taken to Australia. The two talked about the kind of women they'd like to marry. Years later, when the best man met the then-new girlfriend, he knew instantly that she was the one with all the qualities his friend had described.

The best man "had just enough humor and just enough relationship stuff," Marino says. "You really felt like you were getting to know the groom through his eyes."