I wouldn't have believed it in my younger days but now near 70yo, I can cum while still soft. As another poster stated, precum oozes up through my urethra while reading LPSG and watching porn. I edge while doing so but am not usually fully erect.
I've been able to orgasm while using a Homedics massager bu placing my soft cock between the two heads. I've also used home vacuum cleaner hose, placed my soft cock into it, and cum as my cock fluttered inside. Another technique I use when soft is to use one hand to wave my cock back and forth and use my other hand to press and massage my taint. When I get the taint pressure just right, I'll start spurting clear prostate(?) fluid all over. Of course, it sprays back-and-forth from side-to-side all over the floor making a mess to cleanup. However, it feels really good when I get the taint pressure just right.