I don't cry very often, so when I do, it's like a levee has broken. I'll usually end up crying for hours, or on and off for days once I have begun. It's like a whole event when I do start to cry for me because I know the next week will feel like i'm holding a volatile energy within me.
Oddly enough, I also get very emotional when I see people out in public busking or performing in public areas, but I usually have to hold that back because it can be untimely (ex: when i saw a person playing the guitar and singing as Christmas shoppers strolled by in the mall, and ended up having to go to the bathroom to collect myself). Not sure why this happens, but it can be sort of frustrating!
Crying feels natural to me, so I try my best to let it out when the feeling comes.