Here are some other threads that talk about what shifts are like:
https://forums.therian-guide.com/Thread-Can-you-describe-your-most-memorable-shift-as-an-alter-human
^ I even commented on this one, a while ago
https://forums.therian-guide.com/Thread-What-was-your-first-shift-like--23004
https://forums.therian-guide.com/Thread-Is-this-a-shift-animalistic-urge
https://forums.therian-guide.com/Thread-What-To-Call-This-shifting
There are many, many more but these are the more recent and informative ones. Nothing will help you more on here than learning how to use the search function efficiently
For me, I'm usually in a constant canine mentality. Human behaviours are something I have to actively think about and analyze which is exhausting. It's easier when I'm in dog form but if I'm feeling more wolfish, I prefer not to interact with others. If I'm with someone I trust or am going through strong emotions, I stop being able to keep up the human mask well which is usually what I refer to as a shift. I can act normal with effort but I'd rather not.
Shifts are tricky for me since obviously canines have different body language than humans do. I don't have a solid way to communicate without expressive ears and a tail, because facial expressions and speaking don't come naturally to me. Typing with canine emojis on discord is usually how I get through them.