I learned to tightline at the Laura Mercier counter about a year ago and I just love it. If you really want to tightline well, I would recommend the LM products suggested in the previously linked review of the technique.
I may be wrong, but I thought that LM was the one that "developed" the technique. The brush doesn't look like anything special, but it is just right for getting into the lashline. The cake eyeliners have amazing pigmentation and even with my contacts and eyedrops throughout the day, I haven't had any trouble with smudging. It does take a bit of practice, but it's an amazing technique that really makes small eyes look bigger - especially IRL and not a photo.
Although you can use a pencil or fluidline to line your waterline, it isn't really the same as tightlining because tightlining is lining in the lashline, not the waterline. In fact, I often use a Q-Tip to remove any of the line that may have migrated onto my waterline while I was tightlining. Using the LM products, I have had no trouble removing the tightlining with a gentle cleanser and water while washing my face at night.