I have started to do it fully erect and I don't think it could do much harm if the pressure isn't unbearable. It might be better, since you leave less room for fluid buildup. Also that way you're keeping the erection blood in there longer which has more testosterone and DHT in it. I feel like the longer you keep that blood in there the more likely those androgens will attach to the androgen receptors in your penis. Now that's just my theory... don;t know how well this will work. But I feel like it makes sense. But definitely should not over do it since the tunica is much harder during a full erection and it will resist expansion a bit more. So there is a chance it could cause some injury.
