↑The Psychology of Human Sexuality. John Wiley & Sons. 2017. পৃষ্ঠা. 402. ISBN978-1-119-16470-8. https://books.google.com/books?id=ytk5DwAAQBAJ&pg=PT402. "Masturbation refers to all solo forms of self-stimulation focusing on the genitals. Masturbation practices vary widely depending upon the individual's body and personal preferences. For instance, masturbation among women may involve manipulation of the clitoris and labia, stimulation of the breasts, or vaginal penetration with a sex toy. [...] Among men, masturbation most frequently involves using one or both hands to stimulate the penis. Of course, men sometimes utilize sex toys too (e.g., masturbation sleeves, butt-plugs, etc.)."
↑ 11.011.1The SAGE Encyclopedia of Psychology and Gender. SAGE. 2017. পৃষ্ঠা. 1123. ISBN978-1-4833-8427-6. https://books.google.com/books?id=lVYoDwAAQBAJ&pg=PA1123. "Masturbation is the act of touching or otherwise stimulating one's own body, particularly one's genitals, for the purpose of sexual pleasure and/or orgasm. The term is most commonly used to describe solitary masturbation, in which people provide themselves with sexual stimulation while they are physically alone. Mutual masturbation is when two or more people manually stimulate their own body or each other's bodies."