You might have heard the expression “bitten off more than you can chew”. Basically, to have a tiger by the tail means the same, you have taken on something so large or difficult that it could pose a big problem for you.
For example…
In Ashley’s case, she has just successfully negotiated export agreements of her new range of perfume to six countries. She is required to attend formal meetings and promotional events in all six countries. At the same time, she has set up a technology start-up to create software that helps women with their body image. Having the two projects running side by side has meant that she has the tiger by the tail.