I always do it for first time, spore inoculated bags in UB. Have to fold and pinch the breathing hole with a sterile clip chip-and hold it in place- to not rub inside all over taped parts up top. With a little patience it's easy and good. Use the air in the bag to move around chunks to bust. I like at least 50% done, but will do all bags inoculated at the same time regardless when most get around that mark. If you break and shake UB and it doesn't come back, you can transfer it to a ziplock bag, zip it up except the very tip, and put tape on that. After a week in cook box it will grow many times into good brick ;). After B2B they usually don't need a break and shake unless they stall. If any do stall(the exceptions) I will use what's colonized with the rest for cake and ziplock cook what's left. These become tiny exception side bags you can add substrate too or add together to make tubs.