I have two kids now. Life is a bit crazed, but I have noticed a few differences between mothering (or fathering) a newborn the second time around. For example, when your firstborn is two weeks old and cries to be held you pick him up, enter the time you picked him up on your New Baby Excel Spreadsheet, rock him for precisely seventeen minutes, enter the time you put him back down, wait eight minutes to see if he will go to sleep, repeat. When the second baby cries to be held, you hold her.
When the first baby is hungry, you struggle to get into position, carefully check the time, nurse for ten minutes, switch (making sure to switch the safety pin reminder on your bra even though it is useless because you can never remember if the pin means that you started on that side LAST time or that you should start on that side THIS time), nurse for ten minutes, and then write it all down on the feeding chart. When the second baby is hungry, you feed her.
When the first baby is tired, you swaddle him, rock him, shush him, bounce him, carefully lay him down in his cradle and do it all again until he finally gets to sleep. When the second baby is tired, if rocking and swaddling doesn't work within ten minutes, you pop her in the sling and go about your day.
When the first baby is done with one of his nighttime feedings, you go through the whole swaddling/shushing/bouncing routine described above, because heaven forbid he should develop a habit of sleeping with you. When the second baby is done with a nighttime feeding, you weigh the benefits of trying to put her in her own bed against the benefits of just going to sleep with her on your chest. Guess what wins.
And here I had thought that I was a pretty relaxed first time mom back in the day.