Pigpigpig:
Gonna second cooking with heavy cream, so many delicious things you can make with it! Fettucine alfredo is a personal favorite, my gf adds some to scrambled eggs and it makes their texture really fluffy. If you drink coffee you can also replace half and half/milk with heavy cream.
Personally, I'd never drink it straight up, but it works for some people. I'd rather enjoy myself on the way to getting huge than force it.
Heavy cream is best used as a calorie supplement. When you look at it that way, it's a fun ingredient to add to pretty much anything. It's rich, creamy, and adds a good bump in calories. It's also the way you're supposed to use it anyway.
If you drink it straight up, you run the risk of it upsetting your stomach. Some people are into that, so more power to you. However, it won't last as long. And since heavy cream is kind of expensive anyway, that can but a strain on your grocery budget.