May I borrow this pen?" "Sure, go ahead.
"May I use your pencil?" "Sure go ahead.
"Do you mind if I use your phone?" "No, please go ahead.
You should go ahead and do it, just like you said you would.
Once you go ahead and start, even the tiresome work of adding and subtracting figures is interesting in its way.
He was wrong to go ahead with the plan.
He nudged me to go ahead.