Here's a free guitar set for Daz Studio.
Guitar, strap and lead as a wearable preset and also, as separate items included. The Guitar strap is just a first attempt at making one with d-force so might be hit and miss ;-
Load guitar wearable. Yes, the guitar is sticking into g8 so that the strap is not intersecting anything. This will load the guitar, strap and lead all at once parented and in the right positions.
At frame 30 Genesis 8 pose should change. If not load the pose from G8GuitarPoses folder at frame 30.
Select the guitar and apply the Guitar position pose at frame 30.
Simulate d-force using timeline.
There are a couple of quick morphs under morph loader.
Pose guitar lead as req. You could try using the Y-scale on mid sections to lengthen it.
Hopefully it's not too bad ;-)
*Smoothing -set the guitar strap collision to g8 or the clothing. Also simulate clothing first and "freeze" before simulating the strap, Although probably best to use close-fitting, non-dforce clothing for this or it will be going through the guitar.
*If using your own/another pose, then set it at 30-60 frames and also use timeline in dforce simulation settings. The guitar is is parented to G8 hip. Bear in mind that the guitar should stay close to the hip as in the pose provided or d-force might explode the strap.
*If loading separately for use alone or with another figure, load guitar and have it selected when loading strap and lead so that they parent in the correct position
Cheers! -Martin ;-)