^Eh, suck it up, it's not that bad. It's pretty terrible to drink, but simmer it till it's not thick and just chug it and chase with orange juice. I prefer cactus tea to Robitussin, that's for damn sure, and I haven't found the taste to linger personally. I also have found Peruvian torch to taste a lot better than San Pedro.
You know what's really terrible? Eating raw San Pedro. I've done it, but god damn is it bad, that's definitely something I don't want to do again. Especially cause you have to eat a whole foot or more. Bleh.
So to make tea, first you prepare the cactus, which there are a couple of ways to do. I've usually removed the spines and then peeled the skin off in strips (just the translucent layer of the skin, don't peel any green off- it takes forever but the light green right under the skin is the most potent bit). Then I remove the core and slice the flesh into pieces, put them in a blender and blend until it's a goo. Add to a pot, add lemon juice (I usually do 1 lemon per foot of cactus, roughly), and add a tiny amount of water, just enough to turn the slime into a slightly thinner liquid, but it should still be very thick and gross.
I've read of people saying they freeze the cactus slices before making tea to break the cell walls, but I don't know how much effect that really has because I've never done it.
The other way to prep the cactus is to just blend it all up, only removing the core. I've never done it that way.
So after adding the liquid, heat the pot on medium heat, stirring constantly. DO NOT BOIL. You want to bring the tea up to a simmer, but avoid boiling, and stir it very frequently if not constantly. Do that for as long as you can stand, stirring all the time and keeping the tea at a low simmer, hot but not boiling. After 1 hour the tea is no longer the texture of mucus. After 2 hours the tea is fairly thin and has reduced a lot. I've often consumed teas after 45 minutes or an hour, but if you can cook for 2 or 3 the drinking experience will be much better.
Then strain the mixture through a t-shirt into a cup and squeeze the hell out of the cactus that gets caught in the shirt, to get any residual goods out.
Then sit back, grab some orange juice and bread or chaser of your choice, and chug that shit. Expect to feel nauseous, but try not to puke for the first couple of hours, till the drug is absorbed. Then puke away and enjoy the best psychedelic.
It sounds like a lot because it is a lot of prep, but it is 100% worth it. I've come to enjoy the preparation phase actually.