We've just finished an assignment which I had a lot of input into, where I drew out some very tricky diagrams using a particular software programme that I've taught myself to use.
The assignment had an element of group work, but his contribution was minimal - he was to research a particular area, but actually compiled very little data, and that was on the wrong area (somewhere with a similar name).
He has just emailed to ask me if I know what grade I got for the assignment, and whether I can 'help' him to draw a similar diagram for his dissertation.
Seeing as he has neither the software nor the knowledge to produce the diagram, effectively I would be doing this for him. In my own time. For free. Towards his dissertation.
So far I have fobbed him off with the excuse that I have very limited time, and told him where he can source the software.
Incidentally, when we were recently handing in another assignment, 20 mins before it was due in, he handed me his laptop and asked me to write the conclusion to his work because apparently I 'write stuff well'.