My wife and I are swingers from our experience with both of us being with many other people I can share the average sizes posted in the various charts online seem spot on accurate. I have gone from about 6 inches to 7 in length.. and 5.25 to currently mid shaft 6.4 ish.. (and if i fuck a lot it gets swollen to 6.6+). My experience is sex is SO SO SO much more than just size!!!!! First can you stay hard for 20-30 minutes while pleasing a women.. not just fucking her like jack hammer?
I have found that my Girth has biggest effect on women and from that experience would say ideal size might be around 6 inches length... but the Girth has they single largest impact from my experience from a size view point. Anything between 6-6.5 inches mid hard will pretty much please any women as long as you bring the a full game = funny, know how touch a women, smell good (many men do not even in swinging circles), clean shaven, respectful, find the right position that give women the most pleasure (ASK her!! Don\'t guess!!), and show confidence.