Each of my four horses has his or her own drinking style. In some respects, these drinking styles reflect their underlying personalities, I think.
Dawn is a lip flapper. She lowers her face to the water without hesitation, flaps her lower lip a few times at the surface and then drinks deeply. A mare that tests the waters and then fully commits.
Pie approaches the surface of the water several times with his muzzle before drinking. Then he drinks deeply - sometimes with sucking noises. He will always suck his tongue thoughtfully, with the tip protruding from his mouth, for several moments after a first drink. He usually takes a second, shorter drink, and doesn't suck his tongue then. He is cautious, checks things out but is also fond of ritual and contemplation.
Red is a plunger. He directly approaches the water and forcefully drops his muzzle and immediately drinks. There's no hesitation. If he's eating hay at the time, he doesn't finish chewing but drops it in the water, although he's not a dunker - he doesn't eat the hay that gets wet. He's deliberate but also a touch impulsive and very direct about what he wants and how to get it.
Missy drinks a lot and is quite straightforward - she just drinks. She's also my only horse who doesn't have a favorite between the two buckets in her stall - she drinks equally from both. (Red is a right bucket drinker and Pie and Dawn prefer the left - although Pie will also reluctantly drink from the right if his "special" bucket is moved from its usual spot on the left to the right.) She's a plain-spoken, no fuss sort of mare.
Do your horses have drinking styles, and do these reflect their personalities?