You can split the task using the "Spit Task" tool on the toolbar. That
would be the equivalent to adding lag time since a split task begins and
procedes for a period of time, then stands down with work stopping for a
while, and then resumes so work can again procede. You can split the task
as many times as you need. Note that when you do, the suration number
doesnt change because time within the split is considered non-worknig time
and so isn't counted in the duration. If you have a task that runs the
first two weeks in February and split it by a week, the task will now finish
3 weeks after it starts however its duration will remain at 2 weeks.
HTH