Just WORK IT. My recipe is BETTER WORKED EVEN FIVE MINUTES, THAN NOT AT ALL. Don't worry, erect stretches are a one of the best length gains support, we all know nothing comes over night, there are small chances that ONE method works way better than another (I'm talking about manual work here, not devices), we must remember that every single exercise is related to another because this is whole
package, you can't gain length by just stretching, you gotta implement some work into girth as well and vice versa. So my point is, you can't mistake if you work flaccid or erect, if you can maintain erection level 20 minutes and stretching it all the time without losing EQ, phewww that's even better, I'd kill for that time staying erect xD But if you can't, again it is fine it is all GOOD. If you by some case got stuck in plateau. Switch exercises and add intensity bro! Stay cool