Rear-curtain sync (also called second- or trailing-curtain sync) is the ability to time the flash pulse to just before the shutter closes rather than when it opens. This is usually used in combination with a longer exposure to gather ambient light while using the flash to freeze a main subject. With first-curtain slow sync, any motion trails captured by the ambient exposure appear to lead backwards from frozen subject. Rear-curtain makes it look right, but the downside is that it's much harder to get the timing right.
Again, the Pentax AF360FGZ and AF540FGZ can do this, as can the Sigma Super variant and the Promaster 7500EDF and generic Tumax flashes (although some branded variants may not).
All Metz flashes nominally support this feature, but in order for it to actually work, the flash itself needs to have a control. With Pentax's protocol, the setting on the camera doesn't communicate this with a hotshoe flash, so while these models of Metz flashes for other systems might support rear curtain sync, no such luck for us. That means only the 48 AF1 and up support this feature on the Pentax system.
Even though the Metz 36 AF-5 is basically the same as the Tumax DSL88 Series, it does not have the control for rear-curtain sync. On the Tumax DSL886AFZ, what is a two-position on/off switch on the Canon and Nikon versions has an extra position to enable rear-curtain sync. Metz has opted to use leave this out.
On the plus side for Metz, higher-end Metz flashes can do rear-curtain sync in manual flash power mode. Flashes of other makes work only in P-TTL automatic exposure modes, which means that there will be a brief preflash before the start of the exposure.