My T would kind of lead into it like "We have about 10 minutes left." Not that I cared.
Then she would say something like "Time's up for today" or "We have to stop for today," or "Let's pick that up next time."
Obviously not a real effective method for me, because I continued to sit until she gets mad at me and then throws me out.
Personally I think that T should continue until I am done..... DING