Placed glass on side in order to get a container for the theoretical miilkshake ... took picture of glass ... edited it in photoshop ... placed cut out source pic into glass ...selected the front of the glass ...copied and pasted as layer .... filled in the rest of glass behind that layer with colour ... added the copied glass part and lowered opacity... filled glass with general colour of shake behind that copied glass front layer ... used circle selection tool to get shape of top of glass ... used warp to make it bend so to make it spill whilst person in glass treading ...milk shake ...