increasing time until ejaculation

so a couple months i was posting questions about not being able to contain myself with my girlfriend. Now, things are starting to really change. Unlike before, when it would take me only a couple of minutes to ejaculate when masterbating, I can now last much longer, and even somewhat control when i want to cum. Things with my girlfriend, however, have yet to change. I cum within a matter of seconds after she puts her hand on me. Thank God she says it doesn't bother her!! But i did tell her that i would get better with experience.

My question now is, besides continuing to work on things by myself, what would be the first step for me and my gf in order to try getting me to last longer?

One thing we DID start doing is, she gives me handjobs before me start intensly making out so that i don't have to worry about any of that and, to be honest, i absolutly love it!!