HTH Dialog Developers Group

Valeriya doggystyle has sex animation defined in DefineSprite 175
It has long list of frames moving body segments in the loops. First loop starts in frame 1 with frame label "a" for slow speed. The last frame of slow speed contains script tag with gotoAndPlay("a") statement making it play in loop. Right after that is frame with label "b" which is start of middle speed loop. Last frame of that loop has script tag with gotoAndPlay("b") to restart the loop sequence. Next are "c" loop frames. Then there is the last sequence starting in frame with label "x1" for climax. That sequence last frame (last frame of DefineSprite 175) has script tag with stop() statement (instead of gotoAndPlay) to stop the DefineSprite 175 animation in that frame.
Frames are played at constant speed. In each frame you have new body segment placed (another Sprite or Shape), removed or moved.
Shape is simple object like body segment that can't move or change on it's own and can't have a script. Sprite is an object that can have one or more frames, so it can change/move on it's own and each frame consists of one or more either another sprites or shapes.
The animation is done the way that you move (or add/remove) objects each frame.