An endo involves stopping your front wheel and lifting your rear wheel up. Straight endos in themselves are not terribly useful but you can pivot your back wheel around your front end while endoing and that allows you to change direction up to 180 . This is very useful as it enables you to change direction in a very short distance and that has applications on the trail as well as on trials sections.
Skill: Straight Endos.
Situation: Lead in to rotation endos
Learning Environment: Level ground.
Exercise: Endos are not particularly easy to learn since they involve a weight transfer which can potentially flip your bike over, resulting in a real endo! Let us start by considering a simple straight endo without rotating the bike. This involves rolling along slowly and grabbing the front brake while shifting your weight forward. The most common mistake students make is to shift their hips forward. All you get is a lot of horizontal force through your front wheel without getting much upward rotations. Rather, bring your lower body upward and forward. Visualize yourself rotating about your hands. When you do this properly you will find the rear wheel comes up quickly and you must be careful not to flip. As you go up, shift your weight back and extend your arms. If you feel you are going over, let go of your front brake and your bike should flatten out quickly. The objective is to practice until you can bring your rear wheel up and hold it for a second or so. Try to get your bottom as close to the rear wheel as possible. If you can touch your bottom to your rear wheel with your seat down you have pretty much mastered the basic endo. At this level, you are bringing the bike right quite near the balance point on the front wheel and therefore you can start to ask the question: front hops or faceplants?