When I used to make PPT I would have at least 1 liter of tea...if not more....how the FUCK are you plugging that much? Even if it's 1/10th of that, that = 100ml of liquid!!!
Although, I will admit, plugging is a GREAT way to enjoy opiates and especially opium/morphine.
But def not placebo...rectal BA is WAY higher than oral for morphine like 4 to or 8x higher if I remember correctly so if you plugged 100ml or so it might make sense that it has such a strong effect compared to drinking 800 or 900ml.