I'm sure the weight can really be a "strain" when the body is in motion. So a top that holds them better versus, say, one that is elastic, or hands holding them when exposed, probably feels better.
I've found a compromise with my wife, she holds them until I get close. She knows if I grab her hands, I'm close and I want to see them fly. At least it works well for us, while not having her to go 15+ minutes with them flying the whole time.
And one more thing ...
Feel free to post pictures like this, as well as a good snogging. Nothing excites me more than knowing there is a stud out there getting the full experience from such a perfectly formed, ultimately sensual, female companion. The spoon position is also a relaxing favorite of mine, great for not just minutes, but hours of drawn-out pleasure.