It will be much more successful cumming inside as nature designed. All these acrobatics are solely for fantasy. Sperm will not survive as well through saliva and the transfers. Why do you think the clinics directly inject into the uterus or culture in a dish -- to increase chances. If you're already that naked and doing all those things with a man you have no interest in, then clearly it's just for show, even 30 seconds of penetration could lead to a better success
I've donated sperm for lesbians but it has just been straight sex where I cum in the gal wanting to get pregnant. I've always turned down lesbians wanting me to cum in a cup for them (lots ask that) but now if they would do this with me I think I might just agree to donate without being allowed to put my penis in the recipient lol.