Yeah...LSD tolerance is immediate. Back in the day, I used to trip two days in a row. I did discover that you literally had to take twice the amount you took the day before. I would never go for three in a row for all the obvious reasons, but yes...I used to trip back-to-back days, a long time ago, with the help of the "double up" method. I will say that you increase the likelihood of bad trips, or at least significant psychological, secondary effects when you start to get into that. I don't recommend it, for your own mental health. In fact, it was kind of scary because I was already starting out with big doses, probably in excess of 4 to 500 ug of really good LSD, so doubling THAT, in theory, scared me from the get go. Things get very sketchy when you start doubling up, and chances are, if you even desire to do so, you are likely someone who is a risk-taker, and again, it's risky business. I put myself in a very bad way, many years ago, by taking too much LSD. It took a long time to recover, as a side note. Years, in fact, so be careful.