i know lots of track guys dont wear anything under their track shorts because they already usually have a liner in them, but if your concerned I'd recomend a swimmers jock so then it has the thin waistband and the straps at back to still allow for airflow but will keep everything in place, or even just regular tighty whities.
Personally i wouldnt recomend compression shorts under track shorts because i think the look when they stick out below the legs it just looks funny.
Being fairly athletic and run also I too would recommend a good basic runner/swimmer jock. Those liners in the shorts are pretty much worthless. The plus with jocks, they are just plain cooler. Try something basic like the bike brand.
The liner in running shorts won't keep your meat from flopping around. Too much flopping causes chaffing so go for the runner/swimmer jock. If you go with the Bike Brand go large, they are undersized like crazy.
Take it from a sprinter, compression shorts/spandex is the way to go.