Since it's just my fs & me, I'd like to think all our time together is "quality" time -- although I know it's not, like when he's watching his videos (mostly "Rugrats" episodes & Winnie the Pooh) & I use the time to catch up on other things or make dinner. I do try to sit with him, too, though.
I always tell him what the plan is for the day, and if we're shopping, I try to have him help & to find things in it that are fun for him.
Our nightly ritual -- reading books, then listening to a tape with the lights off while I rock him & we talk -- is also a good bonding time.
When I was little, my parents made special time for my sister on me. On one Sunday, one of us would go with Mom, and the other with Dad & we'd do stuff: go out for lunch, go to a park, shop -- whatever -- and the next week, we'd switch. It was great one-on-one time, and it saved my parents from listening to my sister & me argue!
