Repercussions for 2 year old

[BoysRule]

My DS2 is 2.9 and a very demanding child who is forceful, loud and prone to rages. DS1 was not at all like this and was very easy to manage - he hated being told off and was and is rarely naughty. I have spent the past 2 years unsuccessfully managing his behaviour and wanted some advice.

He is beginning to care more about being told off and when at home we use the naughty step. However, when we are out I don't really know where to go with telling off. If I tell him not to do something he will continue. He has massive tantrums at preschool when I drop him off and blows raspberries in the faces of the adults who try to help. I tell him off and try to get him to say sorry but if he doesn't I don't know what to do. I really want to nip this behaviour in the bud - particularly the spitting and shouting he does. I just don't know what to do when he doesn't stop. Threats about taking toys away etc don't work as they are not immediate enough for him. He will behave if I offer him a treat if he does (I do this when I am desperate) but it's not the way I want to go.

Does anyone have any advice?

Thanks

Could you use timeout when you are away from home? I will sometimes sit my DS (2.6) away from everyone else as a timeout. I also know someone who takes a piece of cloth or a flannel out with her as a "mobile naughty spot", would this help perhaps?

Thank you for replying. I guess it feels like there isn't time - for example at the preschool drop off and on the way to dropping my son off at school etc. However, I can see that the mobile naughty spot (particularly if it was pink which he hates!) would work. I would probably only have to do it a few times and then it would just be a threat.