I think it depends on what was intended.
If the intent was to go to completion, but that didn't happen (because of interruption, impotence, poor technique, or whatever), then it counts as a BJ.
If the intent was to play around before the main act (to increase arousal, maintain erection, for variety, etc.) then it's foreplay.
Gena
DS, age 11 and always amazing
“Autistics are the ultimate square pegs, and the problem with pounding a square peg into a round hole is not that the hammering is hard work. It's that you're destroying the peg." - Paul Collins, Not Even Wrong