There is no potion drinking because he drinks them during meditation and he activates the effect using the witcher's ability to "control their metabolism".Honestly I loved the way Thunderbolt was handled, and if there's lots of potions based around giving you a really short burst of crazy effects like we saw there, that's awesome. The way Geralt just went batshit after consuming it, you could practically feel the potion and the intensity/power it gave to Geralt.
However the lack of a potion drinking animation is really disappointing. Frankly that would come as part of the strategy of combat, using crowd control or finding a way to quickly retreat away from a large enemy long enough to consume your potions and then heading back into the fray (As it was in TW1). Thunderbolt would have had even MORE impact behind it if you had to strategically control the Wyvern in a way where you get a spare second to down that potion, or if you'd timed the consumption perfectly as it was landing on Geralt and then moved in on the beast with the power of that potion.