Squishy is a state I've appreciated from a very young age! It may have various names but most men know that stage of erection.
Lots of people have those little habits they unconsciously perform when deep in thought as in daydreaming, reading, watching TV, or when sleepy - like twirling a forelock with a finger, rubbing the short hair on the nape of the neck, tugging on an ear, etc. One of mine is squeezing my penis (not on a bus or in the sauna, mind you!)
In the penis' flaccid state that's no fun at all but as a little more blood flows into it, it actually becomes 'squishy,' sort of like a partially-filled water balloon.
I personally enjoy that feeling and can spend a long time 'squishing!'
As for sex when squishy - I can't count the times! Sometimes squishy becomes brick hard during sex, sometimes not.
But it is an accurate term, sammygirly.
Other guys -- what do you call that state of erection?
Pecker