you're probably wet rather than loose, which is basically a good thing; he just needs to thrust a bit less. Drink may well be softening him but overuse may have the same effect: 3 or 4 times is a quite a lot - no wonder you get sore and no wonder if he gets a bit tired too. The 2nd time generally takes longer to finish than the 1st, and the 3rd longer still. I suspect the answer may just be to cut down a bit (and cutting down on the drink would do no harm).