Advice please

So yesterday I was in bit of a shock during Cecils puppy class. He has been doing so good and lots of improvement at home aswell so im not sure whats going on with him.
He is about 9 months old now and seems to be in a stubborn phase. In class yesterday a tinny little bully puppy joined us because the teacher thought Cecil would be good experience for him since he has been getting along with all types of dogs and all ages. When Cecil saw the puppy he was very stiff and raised his hackles then had one loud bark/ growl at him and started lunging

Everyone was alittle shocked and I stoped playtime for him and the puppy left right after. During class he did well but come playtime with his gf he started out nice, laying on the floor and letting her play with him..but then play got rougher and she yelped a few times when he got ahold of her cheekskin..so I ended play to calm thing down but then the other dog and his gf played and everytime they ran past him he lunged at them! This was new behavior and im not sure what to think of it?- at home with our other dogs he has no problems at all and is such a love bug but I think he still is missing alot of confidence in the outside world.

We have been socialising him since we brought him home and he always had some type of fear but it was getting better so not sure if this is just a phase?
Any ideas in maybe whats going on?

Sounds like the so called second fear Phase where they become stressed in situations they aren't happy with. I'm not an expert with these things so hopefully Liz or Rachel can offer better advice.

Thank you Ian. I noticed his change of behavior for the last 2 weeks in class and im not sure if I should continue the classes because I dont want to put him under more stress or that a nother dog gets hurt. He is also getting more strength so it was very difficult for me to keep him under control and I could see what everyone was thinking about him because of his breed..he is close to 80lbs now. To me he is still a puppy but people seem scared of him

They are all muscular and to those that don't know the breed they can seem very intimidating. Maybe a break for a week or so from the classes, as like you say, it could be stressful for him.

I think this is temporary and to contradict what I've just written perhaps reintroduce the classes after a short break. It's a hard call and hopefully others can offer more constructive advice.

I'd give the actual classes a break for a short while too. Unless your trainer is handling this really well (and I'm assuming not which is why you're asking here), this sort of thing can escalate because of the tension on the lead each time he lunges forwards and you pull him back, and because you will be getting tense and anxious too.

Without being there I can only guess what's happening, but it sounds to me like most of this is triggered by a desire to play and interact, and a response to the lead stopping that. It could also be that there is something about this one new puppy he's not keen on - it happens to us all that there is someone sometimes we don't really like.

Depending on whether your trainer is up for it, what I'd suggest in an ideal world is for you to take Cecil to class to watch quietly at a distance. You may or may not have space for that. It sounds to me like he needs to learn to relax more round other dogs. Hard, I know!

I've recently come across a fantastic trainer called Grisha Stewart (based in Alaska). She's just this last week released her new book that I think would be very helpful for you:

http://grishastewart.com/bat-overview/

I know Cecil's not at the real problem level of reactivity but things can build, so working this way would be helpful to nip it in the bud. You can get the book by download.

Have a look at the website and a read, and see what you think.

thank you so much LizP. I will have look at that this afternoon and hopefully it can give me a few answers in how to approach this the right way!

I think his teacher is a wonderful lady and knows what she is doing when it comes to "normal puppy behavior" but the last few times I have felt like she is not giving the proper attention when the dogs play. I always watch his body language but I think I am missing the guidance in this class now. He knows all his commands very well but I think I am facing a bigger challenge now that needs more attention than the class can offer us.

I will call her this afternoon to inform her of our decision and ill definitely check out this book.

He really is the sweetest pup at home and I hope this is something we will be able to fix.