using shape tweens for cum is something I think we all need to try before realising it totally sucks

I tried so hard to make it work once but with how long it takes to have it not screw up on you you you're probably better off going frame by frame, because yeah it's a little daunting at first but it's not actually that hard.
but Donkey's right. for a first attempt this is definitely better than some, great start. be nice if it stopped at the end though instead of going to the black screen.