Would throwing objects at someone be considered flirting?

Theres this guy friend I have...he was here earlier and was picking up a computer. well out of no where he jokingly throws a penny at me! um,ok. so I lightly threw a flip flop at him:D

I'm involved with someone btw,so I was surprised he even did the throwing. btw,the boyfriend was home:o

my friend was also teasing me as well. just about little things,really. Like on the phone today I said something then he said,"I'm just joking!" (i say that a lot)

any input? is throwing/teasing considered flirting?

thanks!:)