You don't need to have an anatomy book with you all the time to sketch a decent position. It is not as tough as it appears: your strongest tools will be observation and practice. If you ever get the urge to try something new (which I hope you do), it never hurts to look through that anatomy book. Even if your drawing style is far from realistic, the elements that make a pose interesting and credible remain the same: strength, rhythm, action lines, construction, and perspective.
This is why many painters utilize references while depicting the human body. https://setpose.com They references may be in the form of a picture or a video, however these aren't customizable. When you want to sketch a certain position, for example, it might be difficult to locate the proper reference photographs. This is when a movable drawing model comes into play...
Going to Pinterest and utilizing it as a figure drawing reference is a difficult work for experts who have their time down. However, there are several aspects specific to Pinterest that make it a genuine alternative to other websites. To begin, you may establish your own private boards for specific figure drawing references that include a variety of methods, items, body parts, and much more.