I know from a few other posts that other members here have (or had) the same problem as I - unable to come or maintain an erection during sex, especially when covered (which is essential for our activity).
A week ago was the FIRST time I've been able to come with a condom on and without using Cialis.
I'm 30 - definitely not someone who should have to be depending on Cialis to maintain an erection. Being pretty bad with women in general, I've very rarely had free sex. This resulted in a lot of masturbation with the hand while watching porn, which over the years made LB insensitive to the sensations and positions of real sex and created chronic loss / inability to get an erection.
I ended up using Cialis every single time I had sex and even with Cialis I went through at least 10 different types of condoms before finding the right one - (Okamato Mega Big Boy 46mm - a nice way of saying a condom that's not restrictive while still being decently thin).
It was frustrating to frequently resort to a HJ when I just couldn't maintain it during FS.
While in HK I went to a sex shop on the island and bought a few masturbators. The one I liked the best was the US Tenga Soft Tube -
http://www.amazon.com/u-s-tenga-soft-tube-cup/dp/B000S9ND84
It's a disposable, single-use toy but I took it apart so that only the silicone was left and washed it after each use. For the next half a year I used this exclusively with some Astroglide - never ever masturbating with my hand. Laying in the bed, standing in the shower, propped up on my knees, etc.
After I while I noticed that I could now get and maintain an erection while standing or in other positions besides laying on my back (I wasn't able to do this before).
I also noticed that my hand felt rough and actually unpleasant.
I could come without having to watch porn (although I still watch a lot).
A week ago in Nanjing I did covered FS for the first time without any Cialis and to my joy I actually had no problem starting and maintaining an erection. It took some concentration to come but I did it.
I'm relieved. This now means that should I get a girlfriend or another WG, I won't have this sexual dysfunction to deal with each and every time I have sex.
In conclusion, train yourself by refraining from ALL hand masturbation and instead using a masturbation sleeve that you enjoy (maybe a softer one). It took me MONTHS to get there, but now I'm here. On the flip side, doing it with my hand now feels downright unpleasant.