Anything that rolls and is semi firm works well as a roller. I use a PVC pipe, firm pool noodles, a big foam pipe(much harder) from a rubber store as well as my proper rumble roller.
This might sound stupid but... how do you use a foam roller?
Well the basic technique is to put the roller on the floor, sit/lie/lean on it on a certain muscle and roll along the muscle belly. From here there are 2 schools of thought, 1. You find a sore spot and you sit on it for 30s-1min and dissipate the tension, or 2. You just roll away along the length of the muscle. I like a combination of both, I'll find a sore spot and sit on it, then follow that with rolling the length of the muscle. Harder rollers can be used on tendons as well and can have sudden increases in flexibility and mobility. The most important areas to roll are the areas that cop a beating in general day to day life,
- Anterior shoulder - pecs, anterior delt, bicep - this one can be easier with a lacrosse ball against the wall for some.
- Gluteals(all 3) and piriformis
- IT band
- Hip flexors - including the rectus femoris
They are the big 5 in the order I do them. If you have a lot of issues it may take you half an hour(including your other problem areas) to do this and may need to be a seperate session for a while, if there isn't too much going on then it can be part of your warm up.
I mentioned before about problem areas, this is pretty much any other muscle that you know you have problems with, try all the different muscles out, I know my rear delts, triceps and lats get tender because of my joint laxity, as can my calves. If you have tight/sore hamstrings it may not necessarily be the muscle but the tendon, I've seen plenty of clients get an extra 5-10cm on the sit and reach by just rolling the hamstring tendon a couple of times, so make sure you get right up 'under' the glutes to roll the tendons.
After writing all this, I think I'll just make a vid on foam rolling today, pretty well covering what I have just written, plus maybe a bit more. If there is anything you don't get just hold out and see if the vid covers what you need to ask