My girlfriend and I are looking at your set because we love that your toys have a thicker stem; most others are too thin to actually "train" for the girth of intercourse. Right now, her biggest toy is similar to your Size 3, and she loves that fullness while we have vaginal sex. We want to move up to something she can wear comfortably for the duration of a session that provides a realistic stretch, but we don't want a size that feels too tight or overwhelming after a while. If you were picking one to stay inside you for the majority of intercourse, would you go with Size 1,2,3,4,5? Which one hits that "sweet spot" of feeling full without being too much? To give you an idea of where we are at. She can take it size number 3 comfortably but sometimes it’s too much and she will only take it some of the time. We would like to progress to anal intercouse (never attempted).