Self-discipline - for those who are "play before work" types

Any advice on creating & enforcing structure in your own life? How do you discipline yourself to accomplish tasks that there is no one else to motivate you to do (or no immediate consequences)?

I grew up finding school TOO easy (homework was done on the bus ride home, I never needed to study, I pulled projects off at the 11th hour, etc) and my parents did not make me do chores. I have little self-discipline. However, I can muster a LOT of self-motivation if I care enough, and then discipline is not even an issue, as I just do it cuz I want to. The problem is when I don't care, or not enough, but I know I NEED to care.

I'm a play before work type, and I am deadline oriented. This can mean if I have no deadline for a task I don' care to do, then I just continue to goof off. I've tried promising myself some reward upon finishing some task, but that doesn't always work. I've tried denying myself something, like a form of punishment, until the task is done, or if it's done late, but that does not work either.

How do you create motivation for something you really don't want to do but need to do?
I realize a lot of this is mental, so any tips on how to "reason" with yourself to get the right mindset is appreciated. Keep in mind, I don't respond well (or at all) to "tough love".

Thanks.