Our bottle is specifically made to be super flexible to enable you to customize the effervescent bubbles and water flow on your lashes.  Yet durable enough for many repeated uses. The eyecup is oval in shape to comfortably fit around your eye.  Just fill with lukewarm water (no hotter than 98º) and put the eyepiece up to your soapy lashes.  With your eyes closed, squeeze the bottle.  The internal straw brings the liquid up and through the 25 cute little pin holes in the bottom of the eyecup to rinse any cleanser away.  It usually takes a couple of squeezes to completely rinse one eye.  There will be enough liquid in the bottle to repeat with the opposite eye without having to refill the bottle.