School counselor? Pastor??? Holy c&%p, that's terrible advice! Either of those would run screaming from the room for fear of a career-ending scandal.
Mom's a nurse: As long as she's not some kind of crazed fundamentalist, she's not going to be freaked out by the idea of a 16 year old masturbating. Tell mom you feel sexual urges but would like to remain a virgin and she will likely be thrilled. Then ask her to go shopping with you at your local chain drug store. Look around in the section where they have adult diapers and bedpans, etc. Most such stores sell the kind of vibrator you need: Sold as a "body massager", with a 2-3 inch diameter soft ball on the end of a wand that is 12 to 14 inches long. This will have a power cord, not batteries. Hitachi and Oster both make nice versions of this.
Find one of these in the drug store, and then ask mom to buy it for you if you are too shy. She's been buying all sorts of "intimate products" for years, so it shouldn't be a big deal for her. She might even surprise you and ask if you would just like to try hers!
When you are ready to try it out, forget about everything you ever saw in a porno film or website. No penetration is necessary or advisable. Just try it gently on various parts of your body. Try the different speed settings. You'll know when you get there.