That’s a stereo 1/4” phone plug. You wouldn’t want to use that on mono jack on your guitar. It could short out one of the channels on your amp. You can do this, but I would run your guitar with a normal guitar cable into a small 4-channel mixer Like this one. This will allow you to use the gain on the mixer as a pre-amp, and you can mess with the tone and I think it even has effects (echo, reverb, like that). You can then set the output level so it should be at line level and connect the it to your receiver’s aux port with normal RCA cables. Just make sure you start with the volume level on your receiver low and bring it up to the level you want. Also when you are plugging and unplugging the guitar to the mixer make sure the gain for that channel is all the way down or the main out levels are at zero so you don’t get a spike sent to your receiver. You could also hit the mute button on that channel while pugging or unplugging.

By turning the main out level down but putting the input gain on the channel your guitar is plugged into you can even get distortion. It will probably sound like shit, but you can do it in a pinch if you don’t have a distortion pedal.