Aeration ?

I understand the importance of aeration before pitching the yeast however I made the mistake of waiting too long to pitch the yeaast after the beer was aerated (Damn giants game ! ). I did a split 10 gal batch with a friend and his took off like a rocket, mine fermented but not nealry as much as his. I'm already five days in from orignal pitch date, is there anything I can do to try and increase fermentation ? Thanks for any and all help.

You can rouse the yeast by moving the fermenter around a little. Also you can put it in a little warmer area to get the yeast going again. Neither will help if it's already fermented. Have you taken a hydrometer reading? You friend's may have been warmer to begin with and that's why his took off like a rocket. If that's the case yours might taste better?

You can re-pitch but I wouldn't just hold off you beer may take a little longer to get to where it tastes good

How do you know you have to "increase" fermentation, whatever that means?

Have you taken a gravity reading?

What was your OG, your current SG and what temp are you fermenting at?

When you aerate, you're not superoxygenating the wort as far as I know. You're just replacing the O2 that gets boiled out of the liquid. So you're not going to lose the O2 by waiting. Someone contradict me if I'm wrong.