When I was driving my old Caddy more often, I would smoke on the way to school. Definitely couldn't concentrate on it heavily, so I rarely grabbed the good stuff, but I found smoking definitely relaxed me a lot and greatly enchanced the otherwise shitty 30 minute rush hour drive.
I've been using the afforementioned window trick when finishing off a cigar in my car, and I've found it to work wonderfully.
I've been using the afforementioned window trick when finishing off a cigar in my car, and I've found it to work wonderfully.