This question only applies to On-Prem databases as Cloud licenses are assigned to each user where as On-Prem database licenses act as "First Come, First Serve".
If you are using Profile R10:
Click System Admin Tab, General Maintenance, License, Usage.
If you are using Profile V11:
Click System Admin Menu, General, License, Usage.
This will show you all current sessions of Profile running and the additional information on those specific sessions.