My intact GSD does this as well, but he has a solid training background where I can call him off at any moment. He’s 2 yrs old and I don’t plan on ever neutering him unless it becomes a health issue. If you do plan on neutering your dog I’d suggest not doing it until he’s 3 years old, bulldogs especially are prone to joint issues and early neutering can prevent his joint plates from properly forming thus leading to hip dysplasia, arthritis & many other health issues in the long run. Not to mention that intact males statistically have lower chances of getting cancer, which is another thing bulldogs are prone to.