You said: "I do not mix it, I sip the oil with a straw and chase the sips with the straight lemon juice."
The flush works much better (and is MUCH easier to drink) if you mix the juice and the oil like the Dr. Clark and the old "Grandma Nada" recipe reccomend. This liquifies the oil (makes it watery), and you should be able to drink it down in under a minute. I've tried both ways, and by mixing them, it's much easier and I get out more stones. Another helpful hint: using "extra light" oil is easier to drink than extra virgin...