In both cases it sounds like a lubrication issue. Being careful what I say, but tons of foreplay needed - make sure you've had at least one orgasm from oral, fingers, toys first. Too many men, too keen to get on with the deed. Using artificial lube can also help. You need to feel comfortable, safe and aroused. If you are worried it will hurt, it will stop you relaxing, prevent you getting turned on and not produce natural lubrication.