Well, I have to issue an apology. Yesterday my student and I took a x/c down to PHX. Everything went really smoothly, quick in and out at 1630 local time. Except I pretty much botched the arrival...approach told us to PLAN to follow an Alaska 737, and I heard FOLLOW the 737. So I told my student to turn and fall in behind him. Thirty seconds later approach was all over my case saying I needed to listen up and pay attention, now Alaska was too close to me (apparently we were keeping up???) and he couldn't let him descend. Approach asked Alaska if they could make it (about 3,000 AGL a mile or two out) and AK said "I don't know, we'll see". Long story short, I nearly made a 737 go around in my bugsmasher. They made it, we survived the tongue lashing, and I learned a lesson. With a shameful entry though. So if you were flying into PHX yesterday and some idiot in a 172 wouldn't let you descend, I owe you a beer and an apology.