I don't know if he has used his cum to masterbate but my husband loves to use it as lube for round 2 of anal with me. He says it feels awesome.
I take my fresh cum in the morning and save it for 8 hours in the refrigerator and then I inject it with the syringe into my girlfriends vagina as lubricant. You can’t save it much longer than than 24 hours or starts to change. It’s really a great great feeling.