here's the scenario: your friend has a baby. you want to get her out of the house so you invite her to lunch. that's nice of you, really it is... give her a chance to feel like she could be normal again. I encourage this.
her baby is too little for a high chair so she's holding her baby and eating a salad. this means she can't eat quite as fast as you.
you finish your lunch first.
NOW IS WHERE YOU'RE SUPPOSED TO OFFER TO HOLD THE BABY.
not sit looking bored at your empty plate while she's one-hand eating a salad with her face three feet from the table because there's a baby between her and her lunch and she's trying not to drop lettuce on the baby.
and an epilogue... inspired by something that happened to me in 2010... please try to let her enjoy a nice lunch? she's been on maternity leave, you're one of the three adults she's gotten to talk with in the last two months, she got dressed and showered which is a big deal.
I had some ladies invite me out, since I'm that kind of mom I noticed when they were done eating and said "here hold this?" so I wouldn't do the one-hand baby thing, and then one of them seriously said to me, "She's grabbing my clothes, shovel it in, mom!" just to make it clear that my pesky decision to get pregnant, have the baby and then accept a lunch invitation should be appropriately punished. you're a mom now, you don't deserve a nice lunch, get it?
then don't invite me out to rub it in! I didn't tell you to come to my house and babysit, don't ask me to come entertain you and assure me that you'd LOVE to see cute baby and then shun us all the second you decide you're done.