Squirting for the first time (or trying to)

My boyfriend and I have talked for a while now of trying to make me squirt. We are both really turned on by the idea. We have tried several times and let me tell you the trying process as felt amazing but nothing every happens. Last night we tried again and he looked so disappointed that he's not able to make me squirt. Any advice, tips would be greatly appreciated. I don't want him to things less of himself if it's something wrong with me.