I'm only aware of squirting once. I know as apparently I got him right in the eye. However, gushing I have done lots of times, with the first time being during my swinging days. I can not do it to myself and it is a definite technique that works on me. Men that know what they are doing, can get me to gush in seconds and now and again it happens during penetration.
What makes me gush? I'm told the technique that works for me is a rapid and fairly firm fingering over the g-spot, a bit like a royal wave from side to side. It is quite an unusual feeling and if it happens a lot you do feel really dehydrated and heady.
Through penetration it tends to be banana shaped cocks that make me cum most and ones that are around 5" to 6" that make me gush. I guess it must be the constant rubbing and hitting of the g-spot again and a little nipple tweaking also helps with the orgasms as well.
I haven't gushed for a good couple of months and if someone requests it, then it is not likely to happen, as I have to be totally relaxed and turned on, so being under pressure to perform, is no good at all. I love it when it does happen though.
In contrast a friend of mine gushes bucket loads and a lot more frequently than me. I'm glad I don't do it that often, her sheets must get into a terrible state. She should have plastic sheets lol.