A couple of weeks ago I was at the vets with Charlie and Lola when I mentioned neutering. He told be that they both we'ren't really and to leave it another 2-3 weeks as he wanted Lola to catch up in size and weight to Charlie. Charlie was 20 weeks old yesterday and Lola is arounf 17 weeks old. I am currently trying to get Lola to gain weight as the vet won't take her in until she weighs 2kg (she's currently 1.8kg). This evening Charlie has starting following Lola round with his nose stuck to her back end. He keeps trying to mount her or butes her neck. The vets won't take them in over the weekend and I am worrying that we're going to have an accident. Lola isn't showing any signs of being in heat, but can anything happen?