Sounds like a crudded up starter to me. JD and I both went through this. The starter is at the bottom front of the bike and consequently some fine silt creeps in and you get a "flat spot". That is why the rocking it back and forth in gear with the clutch out (not started yet) gets past that flat spot and it starts just fine.
Now the fix is cheap. Take the starter off (do this during an oil change since you will get oil coming out when you pull the starter motor) Take it apart and use a fine sand paper to clean it up. Reassembly and you should be good to go for a while. Bulldog also has some rebuild kits available if you find out you have some bad brushes etc.
If you let it go it will get progressively worse
Patriot Guard Rider
2000 VN750 Sere (Serendipity)
1990 GL1500 (Ole Blue)
1986 VN750 EVie (project bike, heavy custom)
VROC # 11628 / 25000-H
ARVROC # 12 Coordinator and Crowd Control
OKVROC # 18 (H)
TNVROC # 45 (H)