I have always found the last nap the trickiest to get. They are tired from the day but also already had 2 good naps. TBH, I have often APOP-ed it in buggy, sling or car, more so with my 2nd child as it usually fell at a time we were on our way home from somewhere or trying to prepare a meal. It's the first nap they drop & also important to get to BT without getting OT, so I have never been too bothered about AP-ing it.