Step 1: Look like a normal suburban mom. Preferrably in the normal suburban mom uniform of Lululemon. Looking like a normal suburban mom also means you have to look a little rushed and under pressure, but also sport perfect eye makeup and hair.
Step 2: Carry a normal looking bag. Not a bag with any knitting or crafting reference. A bag such as a those made by Coach, or Kate Spade, or Burberry. Truly, any high end bag (and make sure you refer to it as a bag, not a purse) will do.
Step 3: Take your child to their activity of choice. Swimming lessons, soccer, fencing. Whatever your uber-suburban pre-schooler is into at the time.
Step 4: Get your child appropriately introduced to the activity. Make sure they are comfortable in their surroundings. Give them a hug, whatever you need to do to urge them into full participation.
Step 5: Step back. Take a seat with the other normal suburban moms. Observe your child for a few minutes, give them a wave and a smile, then throw them a kiss.
Step 6: Engage in idle chit chat with the women around you. Discuss your child's other activites, how great they're doing in their new school, how excited they are to be swimming/soccer-ing/fencing. Make the other mothers truly believe that you too are a normal suburban mom.
Step 7: Now, this is the key to the Freak out. While talking to the other mothers, slowly and methodically, pull .... out ... your ... knitting.
Step 8: Wait for it. Wait for it. There is it. Shock, furtive glances, chairs turning. You have accomplished the freak out. It usually, in my estimation and experimentation, takes approximate 1-3 minutes for this to occur.
Then you have it. Peace and quiet. You are no longer forced to engage in the idle chit chat, or the comparisons of Bobby Sue's* busy after school schedule or Johnny's* difficulty with his Montessori program. You can sit, watch your Punk swim with an amazing all-encompassing grin, and knit in peace. It works, I can guarantee the results.
*note that these are made up names for the other children that were there. Also note that no normal suburban member of the mom-fia would name their children Bobby Sue or Johnny. I have yet to come across any children with these names in my uber-suburban neighbourhood.