So, if we go back to the mission we flew last Saturday, Goose's "Deep Strike" mission, we could have used wypt designate to slew the TGP onto the first target, designated it, then UNdesignate the TGP, choose the next weapon station, wypt designate to being the TGP back over the target wypt again and slew it to the next target, designate it and now we are ready to drop both bombs on the two primary targets as soon as they come into range. If we had been carrying 4 GBU-38's on the inboard pylons instead of Mk-83's, we could have used the same technique to set up the secondary targets as well. You will notice that Cap is doing all of this slewing and designating and undesignating while the mission is in "Active Pause", which allows him to do all of this without moving towards the target at all. That is a very good training aid to help develop your muscle memory for all of the button presses necessary for this operation. LShft+Win+Pause is the toggle for that if you'd like to use that in a SP training mission.
Of course, this is all just to be able to utilize the TOO mode (Target Of Opportunity) instead of the PP Mode (Pre Planned), which would involve a whole bunch of typing in of coordinates assuming that the mission builder provided them to us in the brief.