He did, since that was the first present ever that Tobias made for him.  Harry has finally gone past the jealous stage, I think, since Sev & Alaina hvae been going out now for a year by the end of the chapter. I agree with the strangers lesson, it's a good thing to know and to review. 

As per the spanking, Severus can amend the number of spanks he gives when taking in the seriousness of the offense, in this case, it was pretty damn serious--people could have died as a result of their "innocent" little prank.  Harry knows this, and he knows also that he deserved it.  Plus, I've stressed several times that it's not really the spanking itself that makes Harry cry so much--yes it hurts, but it stings, Severus does not leave marks, and it stops hurting after ten minutes--Harry really gets upset because of Sev's disappointment and anger with him, and it hurts more than the actual spanking.   That's why the first question out of Harry's mouth when it's all over is "Are you still mad at me?"  And yes, that is the reason Harry  can talk about it to Lexy, it was just, done and over with, and he wasn't traumatized by it.  Abuse, like Lexy's, on the other hand, is never justified, scares the child to bits because there IS no reason for it, and hurts way more than necessary because the abuser is out of control.  Another reason why Sev does not punish Harry the same night of the prank, because he knows he's still too angry and might lose it and truly hurt him. 

Even Sirius knows when to duck and run, LOL!  And Sev's flashback was traumatic for both of them, because neither of them were expecting it.  But that's how victims of years of abuse react sometimes when they're under stress, even when they think they've come to terms with what happened and have "put it behind them" so to speak, they can still have flashbacks or vivid dreams years later, even after therapy and counseling.  My niece's husband is a psychologist and he told me of several cases in which that occured, which served as my model for Sev's reaction.  The mind is a very powerful thing and it can be quite scary when it decides to act without conscious consent.  But now Tobias will really try and watch what he says and how he says it, so some good came out of that episode.

As for Harry, he is just a normal mischivous devil, and though he doesn't like it when Sev punishes him, he knows it's for his own good. And yes, Tobias is much better than he used to be with his grandson, thank goodness.