Nausea after drinking Olive-Oil is "normal" and "natural", it is a voluntary reaction the body does because the digestive system had never encountered such massive amount of oil all at once, the body recognizes it as "non-food", wanting to expel it out of the system fast as possible. It takes lots of psychological preparation and relaxation before the intake. Not easy!
For the revolting taste, maybe you can try to use a funnel with a short rubber tube connected to the end, sit down comfortably on a coach, insert the tube into the mouth, ask someone else to pour the mixture of oil slowly and VERY CAREFULLY into your mouth, so this way it would not pass through your mouth.
For the question of slow bowel movement: it really depends on how you drink it, and how long it takes you to finish it. If you sip slowly and take like 1 hour to finish 1 cup, the pressure cannot be built up efficiently, so its going to take forever to come out, also, the result would not be as ideal.
The ideal or "correct" way to intake it (whether its Epsom Salt solution, Olive Oil, distilled water or juice for cleansing) is to take big mouthful of it and swallow it, repeat doing so continously till it is finished... for people who do juice / water fast, take a mouthful of water/ juice, "chew" on it for awhile before swallowing, this can ease the feeling of hunger.