I have to take the grey attachment off as my cock does not fit in it, the opening in the hose is too small. Have done this many times, either inside my truck or standing outside with the door blocking my bj. I used to have an old electrolux that fit my cock perfectly, wife was always yelling at me to throw it away cause we had a nice new one. :)
Back to watching this vid again. I love car wash vacs. Always try to try different ones and feel them suck the cum out. Even if I just got blown that day. I still get horny when I pass one in the evening and if it’s deserted enough sit in my car and hold it on my cock just right to just have it shake the cum out of me. Wish I had some other guys nearby with a bigger more private car that could share in the joy of that in person.
Have you tried the exhaust pipe of the car with the engine running? That's of the opposite, but it feels very good to let the exhaust massage of push your dick!