Yay! This is a quick, cheap, effective tactic for speeding up public transit.
Believe it or not, I’ve actually been looking for a cupholder for my bike for a while now. This innovative one is made by Bookman uses a spring to securely / temporarily attach to handlebars. Normally $40, I just got it on sale from Madewell for $12. If you want to get coffee and ride around the Mission with me, use coupon code HIGHSUMMER to get your own :)