Said to a person in a wheelchair:
You shouldn't be riding/driving that thing drunk.
Are both natural?
Does any of them require an "in" after it in the sentence?
Said to a person in a wheelchair:
You shouldn't be riding/driving that thing drunk.
Are both natural?
Does any of them require an "in" after it in the sentence?
Let's define some terms.
to operate the mechanism and controls and direct the course of (a vehicle)
Relating to the previous definition, we must also define vehicle:
a means of carrying or transporting something
Ride:
to travel in or on a conveyance
Let's define conveyance, too:
a means of transport
Is a wheelchair a vehicle? Yes. Is this person in a wheelchair operating its controls and directing its course? Presumably in this case. Is this person travelling in or on some means of transport? Yes, he travels in a wheelchair.
Therefore, the person is by definition driving and riding the wheelchair.
That being said, @CanadianYankee makes a good point in the comments:
"Driving" is really only used for a motorized vehicle.
It is true that one normally drives a car or motorcycle, and it's also true that one normally rides a bike (on being left implicit) but rides in (in being explicitly stated) a car unless they are on the roof and clinging to the bike rack for dear life. Considering the definition of in is conventionally stretched to permit a person to sit in an armchair rather than on it, I would say:
You shouldn't be riding in that thing drunk.
If you choose to use drive, I would say the preposition is optional.
TL;DR: Both are okay, but perhaps you should consider using using or operating for a more natural phrasing.
Riding implies more of a passive interaction with a vehicle, and driving is a direct action one takes with a vehicle. (This is part of the reason why the slogan "don't drink and drive" is effective, apart from the allileration)
In this case, to ride something while drunk is not necessarily a big deal, but directly operating a vehicle would be considered dangerous.
For a person in a wheelchair, it would be more appropriate to say "drive" but it might still seem strange because a wheelchair is more so "operated" than "driven".
If I was pushing someone in a wheelchair while they were drunk, the situation would be pretty safe and the person would be "riding".