Not an odd question at all, I’m glad you asked! Tipping massage therapists (and how much you tip) can vary depending on the situation. If you see a massage therapist at a chain–like Elements Therapeutic Massage, Massage Envy, or the like–then the therapist is actually getting very little of the price of the massage, so a tip is somewhat expected…and counted on. I used to work at a massage chain and there, tips were 1/3rd of my income. As for how much…15-20% is customary. I usually get a $10 tip for every hour of massage (so 1 hour = $10, 90 minutes = $15, 2 hours = $20).
No, I have a private practice. There, I do not expect or count on tips at all. If I get them, great; if not, no biggie, because I’m getting a MUCH bigger cut of the massage price (minus overhead). The same goes for therapists working at a chiropractic or acupuncturist office.
I hope that answered your question, and that you enjoy your massage! If you have any further questions about massage therapy, or if anyone else out there does, please don’t hesitate to ask; just hit the "Contact" link on the top menu bar.