The only time you can actually touch anything in the cockpit (legally) when an aircraft is being operated under Part 135 is if you are qualified under part 135. That means that the operator has ops specs that approve the seat you are flying in, they have a training program for the pilot seat you are operating, you have been through that training program and it is correctly documented, and you have been through the appropriate checkride with your POI or his/her designee. If that is not the case, you can't legally touch anything on the 135 legs, so you can't log anything on the 135 legs. We have clients that request a second pilot in aircraft that only require one pilot. When that happens, the second pilot can't log anything because, although our ops specs allow two pilots, we don't have a SIC training program, and nobody has taken an SIC checkride, so they are only there in the event the PIC decides to go Tango Uniform.

You can log the Part 91 legs if you are appropriately rated and the sole manipulator of the flight controls. We generally log these legs as PIC and dual received, and then make the appropriate entries in the pilot's training folder.