My Husky mix does this too. She will lie behind glass in the sun where it got 50°C (122F)... I didn't allow it during this heatwave because I didn't want to risk it...I love this. My dog loves lying in the sun but gets waaay too hot. It's like he's trying to get a tan.
Here in Belgium it has cooled down a little (27°C today).Nice i will check it out later my dawgs are super lazy cause it's darn hot ! But they go for a swim everyday